Thermally sprayed Zn2TiO4 heating coatings with adaptive electrothermal properties

在前期工作中，开发了一种替代金属加热层的方法，即在钛基上热喷涂半导体加热层，并论证了其可操作性。因为它的优点是在部件表面上的热分布更均匀，并且全平面涂层所涉及的工作量较小。工作温度限制在300°C是最本质的缺点。越界会导致氧化和不可逆转的电阻增加，这相当于对加热层的破坏。使用钛酸锌(Zn2TiO4)可以获得更好的温度稳定性，从而创造出新一代热喷涂加热层系统。借助于Zn2TiO4的性能和应用范围，证明了其温度稳定性。到目前为止，热喷涂涂层的应用仅限于实验室毕业，需要密集的开发工作。悬浮液和前驱体的使用计划是合理的，因为它们具有厚而均匀的涂层微结构的优点。应该检查的一个基本优点是施主对电热涂层性能的具体修改。悬浮喷涂剂的综合开发工作(包括喂料技术、喷射器、悬浮液和涂层的开发)构成了新的锌钛酸锌加热层的基础，供体可以直接对其电热性能进行改性。这项开发工作需要为了解相互作用赢得科学的资金基础。这涉及到第一步考察悬浮液和前驱体的发展，第二步围绕喷涂工艺的影响来研究涂层的发展，第三步分析和了解施主对所得到的涂层性能的影响。需要澄清的是以下假设：a)可以通过热喷涂的悬浮液和前驱体来制备锌钛酸锌涂层。b)锌钛氧化物涂层的热稳定性比TiOx或TiOx/20Cr2O3C)。C)MnO和NiO的掺杂影响了锌钛酸锌加热层的电热性能(如电阻率和热行为)。d)通过使用前驱体，施主可以在层中的混合晶体中产生。(E)采用悬浮喷涂的S超音速火焰钢罐的涂层组织致密，其电气性能优于S超音速火焰喷涂钢罐。这一物质-科学-技术基础将作为应用研究项目的对象编制。在该项目的后期，有可能用MnO或NiO供体替代，以证明长期稳定、适应性强的加热层的既定目标。

In the preliminary works an alternative to metallic heating layers was developed in thermally sprayed semiconducting heating layers on titanium dioxide base and their operability was demonstrated. As advantages are to be called the more homogeneous heat distribution on the component surface and the low amount of workload involved by full-flat coating. The limitation of the operating temperature on 300 °C is the most essential disadvantage. With an overstepping it comes to oxidation and irreversible increase of the electrical resistance what amounts to a destruction of the heating layer. With zinc titanate (Zn2TiO4) a better temperature stability should be achieved and therefore a new generation in thermally sprayed heating layer systems be created. With the help of the properties and ranges of application of Zn2TiO4 the temperature stability was demonstrated. An application as a thermal spray coating is known up to now only in the lab graduation and needs intensive development work. The planned use of suspension and precursor is justified by their advantages concerning a thick and homogeneous coating micro structure.An essential advantage which should be examined is the specific modification of the electric-thermal coating properties by donors. The comprehensive development works of the appli-cants with suspension spraying (development of: feeder technology, injectors, suspensions and coatings) form the base of new Zn2TiO4-heating layers to whose electric-thermal properties can be modified by donors straight.It is necessary for the development works to win a scientific funded base for the understanding of the interaction. This concerns in the first step to examine the development of suspen-sion and precursor and in the second step the coating development around the influence of the spray processes and in the third step to analyze and to understand the influencing of donors on the resultant coating properties. It is a matter the following hypotheses to clear up:A) Coatings from Zn2TiO4 can be produced of suspension and precursor by thermal spraying.B) Coatings from Zn2TiO4 are thermally more stable than TiOx or TiO2 / 20Cr2O3.C) Doping from MnO and NiO influence the electric-thermal properties of Zn2TiO4-heating layers (e.g. resistivity and thermal behavior).D) By the use of precursors the donors can be produced in a mixing crystal in the layer. E) By the denser coating structure to be expected with the S-HVOF can with the suspension spraying better electrical properties are achieved than with the S-APS. This material-scientific-technological base is to be compiled the object of the applied research project. In the later course of the project a substitution of MnO-or NiO-donors is possible to prove the set goal of a longtime stable, adaptable heating layer.