铝合金微弧氧化陶瓷膜的形成过程及其特性

分析了微弧氧化陶瓷膜形成过程，描述了样品表面微区弧光放电现象，并采用Ｘ射线衍射法（ＸＲＤ）和扫描电镜（ＳＥＭ）研究了ＬＹ１２铝合金微弧氧化陶瓷膜的相组成及形貌特征。结果表明，铝合金微弧氧化陶瓷膜主要α－Ａｌ２Ｏ３、γ－Ａｌ２Ｏ３组成，陶瓷氧化膜具有表面疏松层、致密层两层结构。微弧氧化技术是一种非常有前途的新技术。     

Improvement of the spreading effect of atmospheric pressure microplasma jet treatment through shielding-gas-controlled focusing

The spreading effect of atmospheric pressure microplasma jets (APμPJ) on the surface of materials will increase the etching area, and controlling the diameter of the jet can improve the precision of surface treatment. In this work, a two-dimensional axisymmetric simulation model is established to analyze the effect of nitrogen (N2) shielding gas on helium (He) from gas dynamics. In addition, by etching the polyethylene terephthalate film, the relationship between the etching effect and aerodynamic analysis is verified. The simulation results are similar to the experimental results, indicating that N2 shielding gas has a focusing effect which is related to the N2 flow rate, distance difference between the inner and outer tubes, and outer tube nozzle diameter. It is hoped that the results of this work can provide a certain reference for the use of shielding gas to control the jet flow of APμPJ.     

Self-Adaptive Control System for Additive Manufacturing Using Double Electrode Micro Plasma Arc Welding

Wire arc additive manufacturing(WAAM)has been investigated to deposit large-scale metal parts due to its high deposition efficiency and low material cost.However,in the process of automatically manufacturing the high-quality metal parts by WAAM,several problems about the heat build-up,the deposit-path optimization,and the stability of the process parameters need to be well addressed.To overcome these issues,a new WAAM method based on the double electrode micro plasma arc welding(DE-MPAW)was designed.The circuit principles of different metal-transfer models in the DE-MPAW deposition process were analyzed theoretically.The effects between the parameters,wire feed rate and torch stand-off distance,in the process of WAAM were investigated experimentally.In addition,a real-time DE-MPAW control system was developed to optimize and stabilize the deposition process by self-adaptively changing the wire feed rate and torch stand-off distance.Finally,a series of tests were performed to evaluate the con-trol system's performance.The results show that the capability against interferences in the process of WAAM has been enhanced by this self-adaptive adjustment system.Further,the deposition paths about the metal part's layer heights in WAAM are simplified.Finally,the appearance of the WAAM-deposited metal layers is also improved with the use of the control system.     

球磨工艺参数对A12O3弥散强化NiCr合金粉及其

采用不同的球磨工艺制备了A12O3弥散强化NiCr合金粉末，粉末经雾化造粒后，进行微束等离子喷涂（MPS）试验。采用XRD、SEM等方法研究了弥散强化粉末及其喷涂层的微观组织结构及硬度。结果表明：采用较长的球磨时间以及相对高的A12O3含量可以得到组织结构均匀，硬质相弥散分布的球磨粉末，MPS喷涂后涂层结构均匀，显微硬度为原NiCr粉末涂层的3倍左右。     

Triboengineering properties of ceramic oxide coatings under boundary friction against steel

The triboengineering properties of ceramic-oxide coatings are studied during boundary friction against steel 45. Ceramic-oxide coatings formed by microplasma oxidation can be used within a wide range of pressures (8–36 MPa) and sliding velocities (0.05–2 m/s) to ensure lower friction coefficient and wear rate of the materials in contact as compared to a steel-steel pair. The improved triboengineering characteristics of tribojoints with ceramic oxide are attributed to the formation of nanostructures (with 40–100 nm elements) and surface smoothing up to R _a = 5.1 nm. The nanostructure and frictional surface morphology of steel are found to be a result of oil I-40A modification by high-dispersed wear products of ceramics in the friction zone playing the role of a nanosize additive to the lubricating material.     

微束等离子喷涂羟基磷灰石涂层

采用微束等离子喷涂(MPS) 在Ti6Al4V基体上制备了羟基磷灰石(HA)涂层, 并以大气等离子喷涂(APS)为对照. 利用光学显微镜、SEM和XRD分析技术对MPS涂层形貌、相组成和结晶度进行了研究. 结果表明: 在微束等离子喷涂过程中, HA 的分解程度比大气等离子喷涂有显著降低, 除了HA相, 仅形成β-TCP相和非晶相. MPS涂层的结晶度主要受喷涂距离的影响. 喷涂距离较短(<80mm)时, 涂层结晶度高于APS方法制备的涂层. 喷涂距离在130mm时, 涂层结晶度低. 大气等离子喷涂层含有β-TCP、α-TCP、TTCP、CaO和非晶. MPS涂层分解较APS少的主要原因是喷涂过程中HA粒子过热不严重.     

微束等离子喷涂制备羟基磷灰石涂层

采用微束等离子喷涂系统制备羟基磷灰石涂层,通过扫描电子显微分析(SEM)和X射线衍射分析(XRD)对涂层形貌、相组成和结晶度进行了研究.结果表明,随着喷涂电流和离子气流量的增加,羟基磷灰石粒子的熔化和撞击后的铺展更充分,在70～130 mm范围内随着喷涂距离的增加粒子熔化程度增加.适当的喷涂工艺条件下微束等离子喷涂制备羟基磷灰石涂层的结晶度可以相当或高于传统大气等离子喷涂制备的涂层,有利于涂层在体液环境中稳定性的提高.     

新型微束等离子弧焊接电源的研制

鉴于高频电弧具有较强的自收缩作用及较好的电弧稳定性的特点 ,研制了调制型脉冲微束等离子弧电源 .本电源可通过对高频电流的低频脉冲调制调节电弧对焊缝的热输入 ,同时具有电弧能量密度大、主弧空载电压低及起始电流递增和熄弧电流递减等功能 ,适用于铜、钛、不锈钢等金属薄件、微细件的焊接 .     

LY12铝合金微等离子体氧化陶瓷膜的相分布及显微硬度分析

使用Ｘ射线衍射仪和显微硬度度计测定了ＬＹ１２铝合金微等离子体氧化陶瓷膜沿深度方向的相分布及显微硬度变化曲线。