钎剂保护法WC/Cu基钎涂层的制备及其性能

Preparation of WC/Cu Composite Braze Coating by Brazing Flux Protective Method and Properties of the Coating

目前,比较成熟的钎涂工艺基本上采用真空或气保护的方法,而仅以钎剂作保护实现钎涂加工的方法鲜有报道。为此,采用钎剂作保护,通过炉中钎焊的方法在Q235A钢表面制备了WC/Cu复合材料耐磨涂层,并通过组织观察和力学性能测试考察了钎涂层的性能。结果表明,使用粉状铜基钎料在大气环境下焊出的涂层气孔、渣孔等缺陷情况为:当涂层厚度为1mm时,在放大100倍的金相显微镜下观察不到明显的气孔、渣孔,缺陷低于0.3%;厚度为2 mm时,气孔、渣孔等缺陷低于1%;厚度为4 mm时,气孔、渣孔等缺陷接近4%;涂层与基体的结合强度高于涂层的自身强度;WC含量为40%的钎涂层的耐磨性能良好。

WC/Cu composite wear-resistant coating was prepared on the surface of Q235A steel via in-furnace brazing in the presence of brazing flux.The microstructure of as-prepared braze coating was analyzed, and its mechanical properties were evaluated.It was found that as-prepared WC/Cu composite wear-resistant coating with a thickness of 1 mm,obtained in atmosphere in the presence of powdery Cu-based brazing flux,had no noticeable gas holes and scum holes,with the rates of defects being below 0.3%.The rates of defects were below 1%and about 4%for as-prepared coatings with a thickness of 2 mm and 4 mm.In the meantime, the adhesion strength between the coating and substrate was higher than the cohesion strength of the coating,and as-prepared composite wear-resistant coating containing 40%WC possessed good wear resistance.