微弧氧化技术的特点
(1) 微弧氧化处理能力强，可以处理各种形状复杂的工件，能在试件的内外表面生成均匀陶瓷层；对材料的适应性广，除铝、镁、钛金属及其合金外，还能在锆、铊、铌等金属及其合金表面生长陶瓷膜层。
(2) 微弧氧化电解液对环境基本无污染，整个处理过程中无有害废水和废气产生，绿色环保可持续发展。
(3) 整套设备工艺简单，处理工序少，无须经过酸洗、碱洗等前处理工序，除油后可直接进行微弧氧化处理，易于实现自动化生产。
(4) 处理效率高，一般阳极氧化获得30μm左右的陶瓷层需要1~2h，而微弧氧化只需10~60min即可。
(5) 陶瓷膜层与基体以冶金方式进行结合后原位生长，两者结合紧密，膜层与基体有较好的结合力，不易剥落。
(6) 陶瓷膜层拥有比较好的综合性能，如具有良好的耐蚀性、耐磨性、高硬度等，此外还能制备出具有隔热、催化、抑菌、生物亲和性等其他特殊功能的膜层。
表 1列出了微弧氧化与阳极氧化及硬质阳极氧化膜的性能指标对比情况。从中可以看出微弧氧化膜的性能较阳极氧化及硬质阳极氧化膜的各项性能指标有显著的提高。
表 1 微弧氧化与阳极氧化及硬质阳极氧化膜的性能指标对比Table 1 Properties comparison of MAO, anodic oxidation and hard anodizing coatings
| Item | MAO | Anodic oxidation | Hard anodizing |
| Applicability | Wear resisting, corrosion resisting, thermal barrier, insulation, thermal shock resistance, high temperature oxidation resisting, protective decoration | Protective decoration, paint bottom | Aluminum alloys spare parts with wear, corrosion resistance and thermal barrier as well as insulation |
| Voltage/V | ≤750 | 13-22 | 10-110 |
| Current/A | Strong | 0.5-2.0 | 0.5-2.5 |
| Maximum thickness/μm | 300 | ＜40 | 50-80 |
| Oxidation time/min | 10-30(50μm) | 30-60(30μm) | 60-120(50μm) |
| Microhardness(HV) | ≤3000 | 300-500 | |
| Breakdown voltage/V | ＞2000 | Low | |
| Thermal shock | 2500℃ | Low | |
| Environment pollution | No | Special treatment, pollution discharge | Special treatment, pollution discharge |
| Uniformity | Uniform | Sharp angle | Sharp angle |
| Flexility | Good | Brittle | |
| Porosity/% | 0-40 | ＞40 | ＞40 |
| Wear resistance | Good | Bad | Moderate |
| Salt spray test/h | ＞1000 | ＜300 | ＞300 |
| Ra/μm | ≈0.037 | Moderate | Moderate |
| Resistance/MΩ | ≥100 | ||
| Process flow | Cleaning-MAO | Alkali wash-acid pickling-mechanical wash-anodic oxidation-hole sealing | Cleaning-alkali wash-deoxidation-hard anodizing-chemical sealing-sealing wax or heat treatment |
| Electrolyte property | Weak alkalinity | Acidity | Acidity |
| Working temperature/℃ | ＜50 | 13-26 | －10-5 |
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