保护涂层类型（Conformal Coating Types）

XY型（聚对二甲苯）：聚对二甲苯是一种透明的聚合物共形涂层，它是由空气中的气相淀积而成的。这些聚合物本质上是多晶的和线性的，具有优异的阻隔性能，具有极端的化学惰性，并且由于沉积工艺可以均匀地应用于几乎任何表面和形状，包括：玻璃、金属、纸张、树脂、塑料、陶瓷、铁氧体和硅。

Type XY（Parylene )：Parylene is a transparentpolymer conformal coating that is deposited from a gas phase in avacuum. These polymers are polycrystalline and linear in nature,possess superior barrier properties, have extreme chemical inertness,and because of the deposition process can be applied uniformly tovirtually any surface and shape including: glass, metal, paper, resin,plastics, ceramics, ferrite and silicon. 

AR型（丙烯酸树脂）：丙烯酸共形涂层易于应用。它们在室温下干燥至几分钟，具有良好的电气和物理性能，并具有抗真菌性。它们在固化过程中具有较长的使用寿命和低的放热量，防止了对热敏感元件的损坏。它们不会收缩。主要缺点是溶剂敏感性，但这也使得它们更容易修复。

Type AR（Acrylic Resin )：Acrylic conformal coatings are easily applied. They dry to the touch atroom temperature in minutes, have desirable electrical and physicalproperties, and are fungus resistant. They have long pot life and lowor no exotherm during cure, which prevents damage to heat sensitivecomponents. They do not shrink. The main disadvantage is solventsensitivity, but this also makes them easier to repair.. 

ER型（环氧树脂）：环氧体系通常可用作“双组分”化合物。所形成的保形涂层具有良好的耐湿性和高耐磨性和耐化学性。然而，它们不可能通过化学方法进行返工，因为任何剥离涂层的剥离器也会溶解环氧涂层或环氧树脂部件和环氧玻璃印刷电路板本身。修理板或更换部件的唯 一有效方法是用刀或烙铁烧穿环氧树脂涂层。

Type ER（Epoxy )：Epoxy systems are usually available as “two-component” compounds. Theserugged conformal coatings provide good humidity resistance and highabrasion and chemical resistance. They are, however, virtuallyimpossible to remove chemically for rework, because any stripper thatwill attack the coating also dissolves epoxy-coated or epoxy-pottedcomponents and the epoxy-glass printed circuit board itself. The onlyeffective way to repair a board or replace a component is to burnthrough the epoxy coating with a knife or soldering iron. 

UR型（聚氨酯）：聚氨酯共形涂料可作为单组分、双组分、UV固化和水性体系。作为一个小组，所有提供优异的湿度和化学抗性加上出色的电学性能延长。

Type UR（Polyurethane )：Polyurethane conformal coatings are available as single component, twocomponent, UV curable, and water borne systems. As a group, all provideexcellent humidity and chemical resistance plus outstanding dielectricproperties for extended periods. 

SR型（硅树脂）：有机硅共形涂层特别适用于高温服务，高达约200℃。它们具有高的耐湿性和耐腐蚀性以及良好的耐热性，这使得PWA的高散热部件如功率电阻器是理想的。有机硅涂料易受磨损（低粘结强度），并具有高的热膨胀系数。

Type SR（Silicone )：Silicone conformal coatings are particularly useful for hightemperature service, up to about 200 deg. C. They provide high humidityand corrosion resistance along with good thermal endurance, making themdesirable for PWA’s that contain high heat dissipating components suchas power resistors. Silicone coatings are susceptible to abrasion (lowcohesive strength) and have high coefficients of thermal expansion. 

修理和返工（Repairs and Rework）

每个IPC-711和IPC-721规范执行。

Performed per IPC-7711 and IPC-7721 Specifications.