Development and growth of boron-modified and germanium-doped titanium-silicide diffusion coatings by the halide-activated, pack-cementation method
Development and growth of boron-modified and germanium-doped titanium-silicide diffusion coatings by the halide-activated, pack-cementation method
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DOI：
10.1007/bf01046990
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发表时间：
1996-04-01
影响因子：
2.2
通讯作者：
Rapp, RA
中科院分区：
文献类型：
--
作者：
Cockeram, B;Rapp, RA
为了在工业纯钛、Ti-22Al-27Nb和Ti-20Al-22Nb上制备钛硅化物扩散膜，研制了一种卤化物活化渗层组件，可在单一工艺/反应步骤中同时沉积硅和硅或锗。由于硼在TiSi2中几乎不溶，因此在B改性硅化物涂层的表面形成了TiB2层。TiB_2层的厚度由包装中的硼活度和卤化物活化剂的选择来控制。锗在钛硅化物层中溶解，但在掺Ge硅化物涂层中分布不均匀，锗的含量受硅锗比和卤化物活化剂的选择控制。五层B改性硅化物涂层的生长动力学与未掺杂硅化物涂层的生长动力学基本相似。五层Ge掺杂硅化物涂层的生长机制与未掺杂硅化物的生长机制一般不同。并对双层TiB涂层的生长进行了研究。
A halide-activated, cementation pack has been developed to codeposit either silicon and boron or else silicon and germanium in a single processing/reaction step to grow Ti-silicide diffusion coatings on commercially pure (CP) titanium, Ti-22Al-27Nb, and Ti-20Al-22Nb. Since boron is nearly insoluble in TiSi2, a TiB2 layer is localized at the surface of the B-modified silicide coatings. The thickness of the TiB2 layer is controlled by the choice of boron activity and halide activator in the pack. Germanium is soluble in the Ti-silicide layers but inhomogeneously distributed in the Ge-doped silicide coating, The germanium content is controlled by choices of the Si-to-Ge ratio and the halide activator in the pack. The growth kinetics for the five-layered B-modified silicide coatings are generally similar to the undoped silicide coatings. The growth mechanism for the five-layered Ge-doped silicide coatings is generally different from the undoped silicides. The growth of dual-layer Ti-boride coatings was also studied.