Optimized surface roughening by pulsed water jet for stronger thermal barrier coating

铸铁已被广泛用于制造汽车发动机。当汽车发动机发生故障时，它们通常会被更换，因为传统的发动机再制造技术非常昂贵。一种新的再制造技术已经被主要的汽车制造商采用，称为等离子体转移丝弧（PTWA）涂层技术，旨在为旧发动机赋予新的生命，否则将被报废。通过PTWA工艺将涂层涂覆到磨损的发动机缸体的内壁上，帮助其恢复到原始状态。这种创新的再制造工艺只需要很少的原材料，并且在生产新发动机时节省了超过 **50%的二氧化碳排放量。通常，在铸铁发动机再制造过程中，在碳钢的最终PTWA涂层之前形成昂贵的镍-铝（Ni-Al）化学涂层，以增加整体结合强度。这种昂贵的Ni-Al预涂层步骤可以通过使用优化的基底表面粗糙度来避免，并且已经广泛报道用于铝基发动机。与铝合金相比，铸铁很脆，很难通过传统的 ** 粗糙化工艺产生显着的表面粗糙度。**该项目背后的想法是通过一种廉价且环保的高压脉冲水射流技术显著粗糙化铸铁基材，该技术有望产生与Ni-Al涂层一样高的结合强度。基材上优化的表面粗糙度不仅在PTWA涂层期间提供金属扩散结合，而且还将在涂层和基材之间产生机械互锁，从而增加整体结合强度。

Cast-iron has been widely used to manufacture automotive engines. When car engines fail, they are typically replaced because**traditional engine remanufacturing techniques are quite expensive. A new remanufacturing technique has been adopted by major**automakers, known as Plasma Transferred Wire Arc (PTWA) coating technology, aims to give a new life to old engines that would**otherwise be scrapped. A coating is applied through PTWA process to the inner-wall of a worn-out engine block that helps restore**it to its original condition. This innovative remanufacturing process requires very little raw materials as well as saves more than**50% CO2 emission associated with the production of a new engine.**Generally, during cast-iron engine remanufacturing process, an expensive nickel-aluminum (Ni-Al) chemical coating is formed**prior to final PTWA coating of carbon steel to increase the overall bond strength. This expensive Ni-Al pre-coating step can be**avoided by using an optimized surface roughness of the substrate and has been reported extensively for aluminum based**engines. Cast-iron is brittle compared to aluminum alloys and difficult to create a significant surface roughness by conventional**roughening processes.**The idea behind this project is to significantly roughen the cast-iron substrate by an inexpensive and environment friendly highpressure**pulsed water jet technology that is expected to create bond strength as high as Ni-Al coating. An optimized surface**roughness on the substrate will not only provide a metallic diffusion bonding during the PTWA coating but also will create**mechanical interlocks between coating and the substrate, increasing the overall bond strength.