Using plasma spraying equipment is more difficult than the ordinary gun spraying device: the more trouble is too much fault, and the coating quality is affected by many variables. The working characteristics of the plasma torch by the input power, gas flow rate, the type and stability as well as the influence of the geometry of the plasma jet. Therefore, most of the articles are of a single type of torch results are described, it is to make the variable is reduced to only the input power and the unit of time used by the two air supply volume.

The plasma jet temperature depends on the center line, (except the input power) stable gas thermal properties, which mainly depends on its enthalpy. In section 2.2.9 of this problem are discussed in detail, at the same time also stressed the difference between the radial temperature distribution of different gases. The heat enthalpy or gas content is more important than the average temperature of the plasma, the plasma powder material input, the amount of heat transfer rate is determined for a single particle powder. Minimum axial plasma temperature must be much higher than most of the coating material melting point. In a given volume flow and efficiency (efficiency of the electrical energy into heat energy in a given device) conditions, can be very good to the accuracy of the gas enthalpy.

However, in the equal power and equal volume of gas flow (and therefore equal enthalpy of plasma), its speed (velocity) will depend on the diameter of the nozzle, if we consider the influence of the best parameters of nozzle on the essence of technology from other design details (diameter and location, powder supply holes for powder form), as well as affected by material properties (such as powder quality and the type of substrate) influence, the difficulties and becomes very obvious, therefore, the experience of operation of the spray gun type, before spraying equipment of different types of the application, need to have a certain room.

For the high quality coating, powder supply is very important, whether it is the pressure sprayer, or vibration powder supply device, are not able to absolutely uniform velocity (to obtain uniform coating is required) the powder into the plasma. 用象旋轉(zhuǎn)刮板或蝸桿式供粉器一類的機械裝置已得到了最好的結(jié)果.在穩(wěn)定氣量和載運氣量之間必須維持一合適的比例.運載氣量應(yīng)盡可能的低，以免等離子體的過 度冷卻.有些供粉器用大流量運載氣工作得十分滿意，而在較低的流量時，它們卻完全不可靠.涂層質(zhì)量實質(zhì)上受粉末質(zhì)量的影響，這是普通常識問題;盡管如此， 至今對這個問題還未曾進行充分的研究，大多數(shù)作者采用商用材料，而且只是注意顆拉尺寸及其在單位容積中的分布，對于給定的噴涂距離來說，對其最佳的顆粒尺 寸已進行了較徹底的研究.當(dāng)?shù)入x子噴槍的熱輸出功率增加時，其噴涂距離必須拉長，以免基體材料的過熱，一旦金屬熔滴離開等離子體的熱區(qū)，小液A就凝固得非 ?？?因此小液滴飛行路程必然比大液摘要短些，容許的最大顆拉尺寸取決于材料的種類，必須對供給各個顆拉使其溫度達(dá)到熔點的 Heat and. Melting latent heat. In addition, because of the heat from 0 surface need time to its core, so the particles in the plasma in the leisure stay must be lengthened. Thus, the thermal conductivity of the material has great influence on the maximum grain size. Ceramic materials with low thermal conductivity. The spraying of magnesium oxide and silicon oxide, the results are not satisfied due to the temperature range is between melting point and boiling point of these materials are narrow and low thermal conductivity of the particle surface temperature reaches the boiling point, at the same time, because of their evaporation, lose a lot of heat. Results top school in plasma residence time in the central heating and melting.