Description:FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)

1. TITLE OF THE INVENTION: “AN ANGULAR BLADE COATING COMPOSITION AND PROCESS THEREOF”
2. APPLICANT:

(A) NAME : NEOPLAST ENGINEERING PVT. LTD.
(B) NATIONALITY : INDIAN
(C) ADDRESS : PLOT NO: 43, GIDC, INDUSTRIAL ESTATE
PHASE-L, VATVA
AHMEDABAD 382 445

3. PREAMBLE TO THE DESCRIPTION
PROVISIONAL

The following specification describes the invention.  COMPLETE

The following specification particularly describes the invention and the manner in which it is to be performed.

FIELD OF THE INVENTION

The present invention relates to an angular blade coating composition and process thereof. More particularly, the present invention relates to composition and process for applying a high performance, wear resistant coating onto angular blades through Laser Metal Deposition (LMD), Tungsten Inert Gas (TIG) welding or Plasma Arc Welding (PAW).

BACKGROUND OF THE INVENTION

In various industrial applications, particularly in the field of heavy-duty material processing and mixing, metal blades are subjected to highly abrasive, corrosive, and high impact environments. These tough working conditions often cause the blades to wear out, break down or fail quickly which in turn leads to frequent repairs, unexpected delays, and lower efficiency during operation.

Angular blades are commonly employed in large-scale mixing equipment and typically fabricated from iron or steel based substrates due to their structural strength and cost effectiveness. However, these materials alone often lack the required resistance to wear, impact, and corrosion, particularly in demanding industrial environments such as chemical processing, mining, oil & gas industry and material recycling.
Conventional surface treatment methods, including hard facing and thermal spraying have been employed to improve the surface properties of such blades. While these techniques may offer some degree of enhancement but they frequently suffer from key limitations such as inadequate bonding with the base metal, uncontrolled dilution of the coating material, porosity and poor microstructural integrity. These shortcomings lead to premature coating failure or insufficient wear resistance under harsh conditions.

Despite these advancements, challenges remain in developing a coating process that provides optimal material selection, process control and structural integrity especially when applying hard materials like tungsten carbide (WC) onto iron substrates without compromising their performance or causing brittle fractures.

Tungsten carbide (WC) is well-known for its exceptional hardness, wear resistance, and high-temperature stability. However, its application in coating processes requires precise thermal control to avoid melting, disintegration or detachment during deposition. Furthermore, the choice of binder material, its interaction with the substrate and the distribution of hard particles within the soft coating matrix play a crucial role in the overall performance of the coated blade.

Additionally, in many operational settings, indirect factors such as environmental exposure during storage, transportation or varying field conditions like humidity, corrosive chemicals or airborne contaminants can further contribute to degradation. Such challenges necessitate a coating solution that can be tailored not just to the immediate wear conditions but also to the broader lifecycle of the component, depending on the service environment.

The patent application number CN110318039A relates to a cutting tool and its manufacturing method. The tool includes a substrate that is coated with either a single layer or multiple layers of coating. Among these layers, at least one layer is composed of a (AlₓSiᵧTi₁₋ₓ₋ᵧ)N coating, where x is ≥ 0.70 and y is > 0 and ≤ 0.1. This coating provides high aluminum content, and the addition of silicon promotes the formation of an amorphous nanocrystalline structure, which refines the microstructure. The (Al-Si-Ti)N coating is limited by its very thin layer thickness, making it non-repairable once damaged, and its brittle nature makes it prone to cracking under high impact or shock loads.

The patent application number JP2002249843A provides a composite material with hardness, strength, toughness, and a method for manufacturing it. The material is made by combining non-oxide ceramic particles (such as TiC, TiN, TaC, NbC, VC, or Cr₂C₃) with metal particles (primarily Fe-based), and applying a boron compound solution to the surface. The compact is then sintered in a nitrogen atmosphere. The composite material described is although offering better hardness and wear resistance but limited by the complexity of its sintering process and the difficulty of applying it as a coating to large or complex geometries.

Thus, there is a strong need for an optimized coating composition and deposition process that effectively integrates hard tungsten carbide (WC) particles into a ductile metal matrix, applied through controlled methods such as laser diode-based Laser Metal Deposition (LMD), TIG welding, or Plasma Arc Welding (PAW). Such a solution must ensure enhanced impact, abrasion, and corrosion resistance, strong adhesion to the substrate, minimal dilution, and long-term operational durability under harsh industrial service conditions.

The present invention addresses these needs by providing a specially engineered angular blade coating composition and deposition process designed for high-performance industrial mixing tools. The coating is applied with the deposition process based on the wear profile and operational demands, where the process can be selected from: laser diode based Laser Metal Deposition process (LMD) or TIG welding or Plasma Arc Welding (PAW). It provides superior wear resistance, dimensional stability, and structural integrity, particularly in harsh and corrosive environments which makes it highly suitable for high-performance industrial applications where earlier technologies fall short in scalability, adaptability, and real-world functionality. It further ensures the deposition of spherical tungsten carbide (WC) particles composite layers onto angular blades while preserving the hardness of spherical tungsten carbide (WC) particles and maintaining the softness of the binder phase.

OBJECTS OF THE INVENTION

The main object of the present invention is to provide an angular blade coating composition and process thereof.

Yet another object of the present invention is to formulate a coating composition comprising spherical tungsten carbide (WC) particles and Fe/Ni/Co matrix which is optimized for toughness, hardness, and durability under severe operating conditions.

Another object of the present invention is to develop a coating process for angular blades designed for large scale industrial mixing tools that enhances their wear, impact and corrosion resistance.

Still another object of the present invention is to maintain the structural integrity of spherical tungsten carbide (WC) particles during the coating process by precisely controlling laser power, spot size, temperature and deposition speed.

Another object of the present invention is to develop a surface engineering process incorporating laser diode based Laser Metal Deposition, TIG welding or Plasma Arc Welding (PAW) which enables both automated and manual application on complex geometries.

Another object of the present invention is to ensure a strong metallurgical bond between the coating and the iron substrate with minimal dilution and reduced carbide precipitation.

Yet another object of the present invention is to enable repeatable and scalable coating applications suitable for field repairs or production environments involving heavy-duty machinery.

Another object of the present invention is to achieve a precisely controlled volumetric ratio of hard (e.g., tungsten carbide WC) to soft binder particles that provides consistent performance in high-abrasion and high-impact environments.

SUMMARY OF THE INVENTION

This invention provides an angular blade coating composition and process thereof. The present invention is specifically designed for largescale mixing tools. The coating composition consists of 55–60 wt% spherical tungsten carbide (WC) particles and 40–45 wt % of a binder phase forming a base material with Fe/Co/Ni. The coating process includes laser diode-basedLaser Metal Deposition, TIG welding or Plasma Arc Welding (PAW). Further, in laser diode-based Laser Metal Deposition, the process employs precise control over temperature (100-200 °C), laser power (1–10 kW), spot size (3–9 mm), deposition speed (300 – 1500 mm/min), and laser wavelength (900-1080 nm), such that spherical tungsten carbide (WC) particles are not melted or excessively dissolved. This composition ensures the mechanical integrity of spherical tungsten carbide particles (WC), while the Co/Ni binder forms a metallurgical bond with the iron substrate of the angular blade. The orientation of spherical tungsten carbide particles (WC)in the soft matrix is finely tuned to resist impact, abrasion and corrosion. The result is a uniform, tough, high-hardness coating with minimal dilution and reduced carbide loss.

While the invention has been described and shown with particular reference to the preferred embodiment, it will be apparent that variations might be possible that would fall within the scope of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The following description includes the preferred best mode of one embodiment of the present invention. It will be clear from this description of the invention that the invention is not limited to these illustrated embodiments but that the invention also includes a variety of modifications and embodiments thereto. Therefore, the present description should be seen as illustrative and not limiting. While the invention is susceptible to various modifications and alternative constructions, it should be understood, that there is no intention to limit the invention to the specific form disclosed, but, on the contrary, the invention is to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention as defined in the claims.

In any embodiment described herein, the open-ended terms "comprising," "comprises,” and the like (which are synonymous with "including," "having” and "characterized by") may be replaced by the respective partially closed phrases "consisting essentially of," consists essentially of," and the like or the respective closed phrases "consisting of," "consists of, the like.

As used herein, the singular forms “a,” “an,” and “the” designate both the singular and the plural, unless expressly stated to designate the singular only.

In recent years, Laser Metal Deposition (LMD) has emerged as a promising surface engineering technique that enables the precise deposition of wear-resistant materials onto metal substrates. It offers several key advantages which includes low dilution, strong metallurgical bonding, minimal heat-affected zones and the ability to tailor coating layers based on application-specific requirements. Similarly, Tungsten Inert Gas (TIG) welding has remained a reliable manual deposition method which is particularly suited for localized surface enhancement or repair in scenarios where automated techniques may be impractical or inaccessible. Plasma Arc Welding (PAW) is another advanced thermal deposition method which is valued for its high energy density and precise thermal control. These characteristics make it well-suited for applying wear-resistant materials to geometrically complex or localized areas, especially where deep penetration and fine-tuned heat input are required. In certain applications, PAW may serve as a complementary or alternative coating method to TIG based welding.

The present invention provides a composition and process for applying a high-performance, wear-resistant coating onto angular blades designed for large-scale industrial mixing tools. These angular blades operate under harsh conditions involving continuous impact, abrasive contact and potential exposure to corrosive materials. To address these operational challenges, the present invention introduces a laser diode based Laser Metal Deposition process, Tungsten Inert Gas (TIG) welding or Plasma Arc Welding (PAW). Laser diode based Laser Metal Deposition process precisely deposits wear-resistant materials onto metal surfaces with strong metallurgical bonding and minimal heat-affected zones. It allows customized coating thickness and composition tailored to specific application needs. Further, TIG welding is a manualmethod ideal for localized surface repairs or enhancements where automation is not feasible. It provides high-quality, controlled welds with minimal contamination. While PAW offers high energy density and fine thermal control, making it ideal for coating complex geometries or achieving deep penetration. Cast WC is a hard, wear resistant material made by melting tungsten and tungsten carbide together. It is commonly used in hardfacing, drilling tools, and wear resistant coatings due to its exceptional hardness and toughness. The coating composition of the present invention consists of 55–60 wt% spherical tungsten carbide (WC) particles, ranging in size from 0.3 mm to 0.8 mm and 40–45 wt% of a cobalt or nickel based metallic binder. The choice between cobalt and nickel as the binder phase is guided by application-specific requirements. Nickel is preferred in corrosive environments due to its superior chemical resistance, whereas cobalt enables higher tungsten carbide loading and is suited for applications demanding enhanced hardness and impact resistance. In the present invention the spherical tungsten carbide particles are infused in the form of pellets, spheres, microcrystalline and macrocrystalline morphology, wherein the spherical tungsten pellets should be in the form of cast WC and microcrystalline with the base material having Ferrous/Nickel matrix. The morphology of the spherical tungsten carbide (WC) particles facilitates even distribution and consistent layering, while the binder phase ensures toughness and metallurgical compatibility with the iron substrate. The main advantage of the present invention is the maintenance of a precisely controlled volumetric ratio of not less than 50% hard particles (e.g., tungsten carbide, WC) to soft binder particles, wherein the WC particles are inherently brittle which are carefully oriented and embedded within the ductile metal matrix to achieve a structurally balanced and durable coating system. This significantly enhances mechanical strength as well as resistance to wear, impact, and corrosion.
As per the process described in the present invention, it begins with carefully preparing the substrate surface through cleaning and activation to ensure proper adhesion. A pre-alloyed or blended coating material containing tungsten carbide within a Fe/Ni/Co matrix is then fed into the deposition zone. Advanced techniques such as Laser Metal Deposition (LMD), Tungsten Inert Gas (TIG) welding, or Plasma Arc Welding (PAW) are employed to deposit the coating with controlled energy input. Throughout the process, parameters like laser power (1-10 kW), spot size (3-9 mm), and inert shielding gas flow (combination of argon/hydrogen or nitrogen/hydrogen) are precisely managed to achieve a dense, uniform, and defect-free coating. Further, the laser diode focus is finely tuned to maximize energy absorption by the binder material without altering the structural integrity of the spherical tungsten carbide particles (WC). This systematic approach ensures enhanced mechanical strength, wear resistance, and long-term durability of the coated angular blade.

Moreover, after deposition the coating exhibits a single-layer structure with uniform thickness, dense microstructure and minimal porosity. The spherical tungsten carbide (WC) particles are evenly embedded within the Fe/Ni/Co matrix in a way that creates a finely tuned distribution of hard (WC) and soft (binder) phases which ensures a balance of extreme hardness and crack resistance. The coating is specifically engineered to withstand three primary modes of wear: abrasion, impact and corrosion. The orientation of spherical tungsten carbide (WC) particles within the metallic matrix, combined with the controlled process parameters prevents precipitation or segregation of spherical tungsten carbide (WC) particles at the bottom of the layer which is a common problem in conventional hard facing techniques. Additionally, due to the low dilution achieved through controlled heat input, the coating retains its designed composition and mechanical performance without being compromised by excessive mixing with the base material. This makes the invention particularly well-suited for high-load, high-speed mixing blades employed in mining, construction, chemical processing, and other heavy industries.

A flowchart illustrating the angular blade coating process by Laser Metal Deposition (LMD) according to embodiment of the present invention.Theprocess comprises:

Step 1: cleaning the surface of the angular blade and ensuring surface activation to promote strong metallurgical bonding.

Step 2: analyzing the composition of the pre-alloyed WC-Fe/Co/Ni rod, wire, or cord and ensuring appropriate spherical WC size of 0.3-0.8 mm, uniform structure, and hall flow for stable feeding.

Step 3: configuring a diode laser system with 1-10 kW power, the spot size is adjusted between 3–7 mm based on the angular blade geometry, and the wavelength is selected between 900-1080 nm to match the absorption characteristics of the 35–65% Fe/Co/Ni matrix.
a beam overlap of at least 40% is maintained, the laser scanning speed is kept at a minimum of 400 mm/min, and the temperature is controlled between 100–200 °C to preserve the structural integrity of the spherical tungsten carbide (WC) particles and enable controlled melting of the Fe/Co/Ni matrix phase for achieving strong metallurgical bonding with the iron substrate.

Step 4: positioning the rod, wire or cord feeding system to accurately deliver the coating material into the laser-induced melt pool with precise control over feed rate.

Step 5: feeding the pre-alloyed WC-Fe/Co/Ni rod, wire, cord into the laser-induced melt pool, where it melts to form a dense, metallurgically bonded coating and also supplying inert shielding gas (combination of argon/hydrogen or nitrogen/hydrogen) preventing oxidation during deposition.

Step 6: maintaining stable melt pool conditions by controlling heat input to achieve low dilution, thereby preserving the designed composition and mechanical properties of the coating without excessive mixing with the base material.

Step 7: allowing controlled cooling between layers to minimize thermal stresses.

Step 8: cooling gradually the coated angular blade under inert gas, also performing visual inspection, nondestructive testing (NDT), and mechanical evaluations to verify coating quality and integrity.

Step 9: grinding and polishing the surface to achieve the required dimensional accuracy and surface smoothness which ensures a high-performance, wear-resistant coating.

Furthermore, for geometrically challenging zones such as deep angles, notches, or curved surfaces, TIG welding is employed as a complementary deposition process. It enables manual application of the same composite material with high precision in areas where laser beam access is limited. The use of metal-cord wires filled with the composite powder ensures a consistent material composition during both automated and manual operations. Additionally, Plasma Arc Welding (PAW) may be utilized as an alternative or supplemental method, especially in applications requiring deeper penetration, higher energy density, or semi-automated control in complex geometries. To support all selected deposition methods, composition of the present invention is provided over rod or cord form with a homogeneous blend, a pre-alloyed formulation would be applied, optionally blended for performance tuning. This system results in a metallurgically unified structure upon application, eliminating any separation between the hard and binder phases.

While the present invention has been described with reference to certain illustrative embodiments, it should be understood that the scope of the invention is not limited thereto. Various modifications, adaptations, and alternative implementations will be readily apparent to those skilled in the art in view of the foregoing disclosure, and such variations are intended to fall within the scope and spirit of the invention as defined by the appended claims. , Claims:We Claim:

1. An Angular blade coating composition comprises of:
a. 55–60 wt% of spherical tungsten carbide (WC) particles having a particle size in the range of 0.3 mm to 0.8 mm; and
b. 40-45% of a binder phase forming a base material with Fe/Co/Ni depending upon the spherical tungsten carbide particles (WC) which are uniformly oriented and embedded within the ductile binder matrix to enhance mechanical strength, wear resistance, impact resistance, and corrosion resistance;
a precisely controlled volumetric ratio of not less than 50% hard particles to soft binder particles is maintained.

2. The angular blade coating composition as claimed in claim 1, wherein the spherical tungsten carbide (WC) particles are infused in the form of pellets, spheres, microcrystalline, and macrocrystalline morphology.

3. The angular blade coating composition as claimed in claim 2, wherein the spherical tungsten pellets should be in the form of cast WC and microcrystalline with the base material having Ferrous/Nickel matrix.

4. The angular blade coating composition as claimed in claim 1, wherein the shape of the spherical tungsten carbide (WC) particles is maintained during deposition by controlling laser power of 1-10 kW, temperature of 100-200 °C and deposition speed of 300-1500 mm/min.

5. The angular blade coating composition as claimed in claim 1, wherein the composition is provided over rod or cord form with a homogeneous blend, a pre-alloyed formulation would be applied thereover.

6. The angular blade coating composition as claimed in claim 1, wherein the orientation and distribution of the spherical tungsten carbide (WC) particles within the metallic matrix are arranged to optimize mechanical performance and minimize particle segregation or detachment.

7. An Angular blade coating process comprises of:

Step 1: cleaning the surface of the angular blade and ensuring surface activation to promote strong metallurgical bonding;

Step 2: analyzing the composition of the pre-alloyed WC-Fe/Co/Ni rod, wire, or cord and ensuring appropriate spherical WC size of 0.3-0.8 mm, uniform structure, and hall flow for stable feeding;

Step 3: configuring a diode laser system with 1-10 kW power, the spot size is adjusted between 3–7 mm based on the angular blade geometry, and the wavelength is selected between 900-1080 nm to match the absorption characteristics of the 35–65% Fe/Co/Ni matrix;

a beam overlap of at least 40% is maintained, the laser scanning speed is kept at a minimum of 400 mm/min, and the temperature is controlled between 100–200 °C to preserve the structural integrity of the spherical tungsten carbide (WC) particles and enable controlled melting of the Fe/Co/Ni matrix phase for achieving strong metallurgical bonding with the iron substrate;

Step 4: positioning the rod, wire or cord feeding system to accurately deliver the coating material into the laser-induced melt pool with precise control over feed rate;

Step 5: feeding the pre-alloyed WC-Fe/Co/Ni rod, wire, cord into the laser-induced melt pool, where it melts to form a dense, metallurgically bonded coating and also supplying inert shielding gas (combination of argon/hydrogen or nitrogen/hydrogen) preventing oxidation during deposition;

Step 6: maintaining stable melt pool conditions by controlling heat input to achieve low dilution, thereby preserving the designed composition and mechanical properties of the coating without excessive mixing with the base material;
Step 7: allowing controlled cooling between layers to minimize thermal stresses;

Step 8: cooling gradually the coated angular blade under inert gas, also performing visual inspection, nondestructive testing (NDT), and mechanical evaluations to verify coating quality and integrity;

Step 9: grinding and polishing the surface to achieve the required dimensional accuracy and surface smoothness which ensures a high-performance, wear-resistant coating.

8. The process as claimed in claim 6, wherein the laser diode focus is finely tuned to maximize energy absorption by the matrix material without altering the structural integrity of the spherical tungsten carbide particles (WC).

9. The process as claimed in claim 6, wherein the morphology of the spherical tungsten carbide (WC) particles facilitates even distribution and consistent layering within the Fe/Ni/Co.

10. The process as claimed in claim 6, wherein the coating exhibits a single-layer structure with uniform thickness, dense microstructure and minimal porosity after deposition.