钛表面厚碳化钨涂层研究进展

Research Status Quo of Thick WC Coating on Titanium Alloy Surface

摘要:

钛表面制备厚的碳化钨耐磨涂层的方法主要有喷焊、喷涂、激光熔覆3种。火焰喷焊可在钛表面制备2 400μm厚的WC耐磨涂层,涂层性能稳定,与基体为冶金结合;可通过预活化钛合金表面、增加重熔、中温回火等方式改善涂层性能。采用超音速火焰技术喷涂团聚烧结型的WC-Co粉末,可在钛表面制备4 153μm厚的耐磨层,涂层易出现W_2C脆性相、η反应相;通过工艺控制,涂层孔隙率可小于1%。采用激光熔覆可在钛表面制备2 900μm厚的WC耐磨层,涂层与基体虽为冶金结合,但存在裂纹、气孔等缺陷。3种方法均可制备毫米级厚的WC耐磨涂层,这种厚涂层将大大延长设备的使用寿命。

Abstract:

The anti heavy WC coating can be prepared on the surface of titanium alloy by spray-welding,spraying and laser cladding. The WC wear-resistant coating of 2 400 μm can be prepared on titanium alloy by flame spraying welding. The coating is metallurgical bonded with the substrate,and the hardness changes gradient. The properties of the coating can be improved by pre-activating the surface of titanium alloy,increase remelting processing,and use medium-temperature tempering. The wear-resistant WC layer can be made 4 153 μm on titanium by high velocity oxygen fuel( HVOF) method,the powder is agglomerated sintered WC-Co powder. The W_2C brittle phase and η reactive phase may appear in spray coating. The porosity of the coating can be less than 1% by control the spray process. The WC wear-resistant coatings of 2 900 μm thickness can be prepared on titanium surface by laser cladding. The coating combined with matrix is metallurgy,but,there are defects such as cracks and blowholes. These three methods all can make millimeter-scale coating. These millimeter-scales coating will greatly extend service life of equipment.