Surface Modification of Metallic Materials by Shock Coating

利用冲击能在各种金属表面涂覆硬质材料，这在国际上尚属首次。该工艺被命名为冲击涂层或爆炸涂层。爆炸涂层的原理如下：由于炸药的爆炸作用，涂层粉末被加速并与母材发生碰撞。得到的涂层致密性好，并通过机械锚定效应与金属基体有较好的结合强度。本研究采用了轴对称和新开发的爆炸包覆技术。后一种技术利用了水下激波。涂层材料为TiAl金属间化合物、自熔炼喷雾粉末。采用高能球磨机处理的金属陶瓷复合粉末。使用的金属基体是纯铜和奥氏体不锈钢。得出了以下结论。(1)采用爆速26OOm/s炸药的轴对称爆炸包覆技术，在奥氏体不锈钢棒上完成高密度TiAl和无裂纹自熔喷涂粉末的包覆层。(2)使用水下激波的炸药包层的爆速为69OOm/s。在无裂纹的铜板上制备了高密度的TiAl和TiAl/Ti复合粉末涂层。两种情况下，层的维氏硬度均为400 ~ 60ODPN。(3)对上述涂层进行热循环热冲击试验。经过100次热循环后，所有层仍然完好无损。冲击涂层后的热处理对提高热冲击性能是有效的。

Coating of the hard materials on the various metals has been made by using shock energy in the present study, which is the first attempt in the world. The process was named the shock coating or the explosive coating. The principle of the explosive coating is as follows. The coating powder was accelerated and collided with base metal by detonation of explosive. The obtained coating layer was highly densified and it also had substantial bonding strength with metal substrate by mechanical anchoring effect. The axisymmetric and the newly developed explosive coating techniques were applied in the present study. Underwater-shock wave was utilized in the latter technique. The coating materials used were TiAl intermetallic compound, self-smelting spray powders. Metal and ceramics composite powders treatedly high energy ball mill were also used. Metal substratum used were pure copper and austenitic stainless steel.The following conclusions were led.(1) In the case of axisymmetric explosive coating technique using explosive with detonation velocity of 26OOm/s, the coating layer of highly densified TiAl and self-smelting spray powders without cracks was completed on austenitic stainless steel rod.(2) Detonation velocity of the explosive used in the explosive coating using underwater-shock wave was 69OOm/s. Highly densified coating layer of TiAl and TiAl/Ti composite powders was produced on copper plate without crack. Vickers hardness of the layer was 400 to 60ODPN in the both cases.(3) Thermal shock test of the coating layers described above was carried out by thermal cycling. All the layers were still sound after 100 thermal cycles. Heat treatments after shock coating were effective for developments of the thermal shock properties.