Self melting alloy powder

Self fluxing alloy powder refers to an alloy material in which the powder does not require additional additives during the remelting process and has the functions of self deoxidation and slagging. It can infiltrate the surface of the workpiece and be deposited. This type of material generally includes iron-based, nickel based, and cobalt based alloys, which contain a certain amount of boron and silicon elements.

Metals, alloys, and their composite powders

There are many types of alloy powders, and based on material classification, they can be divided into the following types:

Nickel based alloy powder: Nickel based alloy is the most diverse type of alloy powder. Widely used include:

Ni Cr alloy is widely used as an antioxidant coating at high temperatures;

Ni Cr Fe alloy, can be turned and used for spray repair;

Ni Cu alloy has excellent resistance to seawater corrosion;

Ni-Cr-W alloy can be used for friction wear resistance and high-temperature adhesive wear resistance under oil-free conditions.

Ni-Cr-Al-Y alloy can prepare dense, high bonding strength, chemically stable coatings, high temperature resistance and oxidation resistance, and has developed into multiple series of MCrAlY materials.

Cobalt based alloy powder:

Co Cr Mo Ni Fe alloy has good high-temperature strength, good thermal stability, and resistance to various forms of wear;

Co-Cr-W-C alloy, high hardness, good red hardness, and erosion resistance;

The performance of Co Cr Al Y alloy is similar to that of Ni Cr Al Y alloy, but it is used at higher temperatures.

Copper based alloy powder: used as a surface coating for soft supports; Tin bronze powder, used as an anti friction coating. Phosphorus bronze powder, used as a wear reducing and wear-resistant coating.

Iron based alloy powder: Cr13 series stainless steel powder; Austenitic stainless steel powder containing molybdenum; And high chromium iron alloy powder and high carbon iron alloy powder used as additives for high hardness components.

Other alloy powders: aluminum silicon alloy powders with various ratios, tin based babbitt alloy powders, etc.

Metal composite powder refers to a powder material made by combining two or more different metal materials using non-alloying methods (such as mechanical bonding or chemical bonding). Mainly nickel aluminum composite powder and nickel chromium aluminum composite powder. There are various types of aluminum content in nickel aluminum composite powder, including 5%, 10%, and 20%. It is generally believed that during spraying, nickel and aluminum will undergo an aluminothermic reaction, releasing a large amount of heat to supplement and heat the material, thereby achieving excellent bonding performance; Nickel chromium aluminum composite powder is a composite powder of nickel chromium alloy and aluminum. During spraying, its heat release is more severe and intense than nickel aluminum powder, resulting in better bonding performance and better resistance to high-temperature oxidation.

Ceramics, metal ceramics and their composite powders

Ceramic materials refer to a collective term for metal oxides, carbides, nitrides, borides, and silicides. Ceramic materials have stable chemical properties and high melting points.

The commonly used oxide ceramics include alumina (Al2O3), zirconia (ZrO2), chromium oxide (Cr2O3), titanium oxide (TiO2), and their composites.

Aluminum oxide used for spraying is generally stable α The coating has high temperature resistance, good electrical insulation performance, high hardness, and low friction coefficient. It can be used as wear-resistant coating, electrical insulation coating, and thermal insulation coating.

Titanium oxide has several phase structures, and small changes in composition (deoxygenation) can cause significant changes in appearance, color, and properties. The titanium oxide coating is hard and dense. Adding a certain amount of titanium oxide (ranging from 3% to 50%) to alumina improves the toughness and density of the coating. This material, also known as alumina titanium, has superior fiber wear resistance in its coating.

The chromium oxide coating has excellent resistance to hard surface wear and abrasive wear at 550 ℃. Another advantage of chromium oxide coating is its good self matching performance, which can match well with the grinding pair during sliding friction.

Zirconia has a high melting point and low thermal conductivity, making it an excellent high-temperature insulation material. ZrO2 undergoes phase transformation and volume changes at a certain temperature. When used as a thermal barrier coating, the material needs to be stabilized (commonly Y2O3). Y2O3+ZrO2 is an ideal thermal barrier coating material and has been widely used.

Commonly used carbide ceramics include tungsten carbide (WC), chromium carbide (Cr3C2), molybdenum carbide, etc.

Tungsten carbide is a hard material that is prone to phase transformation at high temperatures, greatly reducing its hardness. Due to the excellent high-temperature performance of cobalt metal, its melt has excellent wetting ability towards WC. Therefore, cobalt tungsten carbide has become the most ideal sprayed tungsten carbide material. Chromium carbide has good resistance to high-temperature oxidation and high-temperature wear resistance. It is often mixed with nickel chromium alloy to improve the cohesive strength of the coating. To improve the wettability of chromium carbide, it can be first coated or composite with nickel or cobalt, and then mixed with Ni Cr.

Ceramic composite powder and metal ceramic composite powder

Ceramic composite powder. Composite of two or more ceramic materials in a certain proportion to obtain better thermal sprayed ceramic materials. The composite method can be agglomeration sintering or melting fragmentation. Aluminum oxide titanium oxide series; Zirconia yttrium oxide, zirconia magnesium oxide, zirconia calcium oxide materials; And chromium oxide silicon oxide titanium oxide materials.

Metal ceramic composite powder. This material has both the toughness of metallic materials and the high hardness and chemical stability of ceramic materials. Their composite methods include mixing, agglomeration, agglomeration sintering, etc. Tungsten carbide cobalt series and chromium carbide nickel chromium series are the two most widely used metal ceramic materials. In recent years, new metal ceramic materials have been continuously launched, which have better strength, higher deposition efficiency, denser coatings, and greater wear resistance: powders such as WC-10Ni, WC Co Cr, and WC CrC Ni obtained by agglomeration and sintering methods.