The aim of this research was to establish whether the shell of green-lipped mussels and Pacific oysters could be plasma sprayed to promote and accelerate the establishment of filter feeder colonies. While CaCO3 degrades before melting under equilibrium conditions, the hypothesis considered in this work was that the high-temperature, highly nonequilibrium conditions experienced by powders during plasma spraying may be sufficient to impart enough thermal energy into the powder, at a fast enough rate, that the CaCO3 phase would melt before undergoing total thermal degradation. Sprayable mussel and oyster shell powder was manufactured by crushing and milling. A range of plasma spray parameters incorporating a wide operating window of plasma power and gas velocity were trialed. Coatings were initially formed from both powders under all plasma spray conditions used. However, the samples degraded into powdery debris with time due to the reaction of CaO with water in the air to form Ca(OH)2. No evidence of CaCO3 melting was found, indicating that it was not possible to form a coating by thermal spraying. The mechanism of inflight particle phase degradation is presented for both powders, along with proposed mechanism of initial coating formation due to melting of CaO.

中文翻译：

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等离子喷涂牡蛎和贻贝壳的 CaCO3 涂层

本研究的目的是确定是否可以对绿唇贻贝和太平洋牡蛎的壳进行等离子体喷洒，以促进和加速滤食动物群落的建立。虽然 CaCO3 在平衡条件下熔化前会降解，但本工作中考虑的假设是，粉末在等离子喷涂过程中经历的高温、高度非平衡条件可能足以以足够快的速度将足够的热能传递到粉末中，使得CaCO3 相会在完全热降解之前熔化。可喷雾贻贝和牡蛎壳粉是通过粉碎和研磨制造的。试验了一系列结合了等离子体功率和气体速度的宽操作窗口的等离子喷涂参数。在使用的所有等离子喷涂条件下，最初由两种粉末形成涂层。然而，由于 CaO 与空气中的水反应形成 Ca(OH)2，样品随时间降解为粉状碎片。没有发现 CaCO3 熔化的证据，表明不可能通过热喷涂形成涂层。介绍了两种粉末的飞行中颗粒相降解机制，以及由于 CaO 熔化而形成的初始涂层形成机制。