保護(hù)涂層類(lèi)型（Conformal Coating Types）

XY型（聚對(duì)二甲苯）：聚對(duì)二甲苯是一種透明的聚合物共形涂層，它是由空氣中的氣相淀積而成的。這些聚合物本質(zhì)上是多晶的和線(xiàn)性的，具有優(yōu)異的阻隔性能，具有極端的化學(xué)惰性，并且由于沉積工藝可以均勻地應(yīng)用于幾乎任何表面和形狀，包括：玻璃、金屬、紙張、樹(shù)脂、塑料、陶瓷、鐵氧體和硅。

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（丙烯酸樹(shù)脂）：丙烯酸共形涂層易于應(yīng)用。它們?cè)谑覝叵赂稍镏翈追昼姡哂辛己玫碾姎夂臀锢硇阅?，并具有抗真菌性。它們?cè)诠袒^(guò)程中具有較長(zhǎng)的使用壽命和低的放熱量，防止了對(duì)熱敏感元件的損壞。它們不會(huì)收縮。主要缺點(diǎn)是溶劑敏感性，但這也使得它們更容易修復(fù)。

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（環(huán)氧樹(shù)脂）：環(huán)氧體系通?？捎米鳌半p組分”化合物。所形成的保形涂層具有良好的耐濕性和高耐磨性和耐化學(xué)性。然而，它們不可能通過(guò)化學(xué)方法進(jìn)行返工，因?yàn)槿魏蝿冸x涂層的剝離器也會(huì)溶解環(huán)氧涂層或環(huán)氧樹(shù)脂部件和環(huán)氧玻璃印刷電路板本身。修理板或更換部件的唯 一有效方法是用刀或烙鐵燒穿環(huán)氧樹(shù)脂涂層。

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為單組分、雙組分、UV固化和水性體系。作為一個(gè)小組，所有提供優(yōu)異的濕度和化學(xué)抗性加上出色的電學(xué)性能延長(zhǎng)。

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（硅樹(shù)脂）：有機(jī)硅共形涂層特別適用于高溫服務(wù)，高達(dá)約200℃。它們具有高的耐濕性和耐腐蝕性以及良好的耐熱性，這使得PWA的高散熱部件如功率電阻器是理想的。有機(jī)硅涂料易受磨損（低粘結(jié)強(qiáng)度），并具有高的熱膨脹系數(shù)。

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）

每個(gè)IPC-711和IPC-721規(guī)范執(zhí)行。

Performed per IPC-7711 and IPC-7721 Specifications.