1、 ENGINEERING MATERIAL SPECIFICATION Date Action Revisions Rev 02 2012 03 20 N Status No replacement named N. Benipal, NA 2006 03 30 Revised Inserted 3.0; Deleted 3.1, 3.2, 3.3, 3.13, 4; Revised 3.7.1 1997 11 11 Activated S. DeGrood Controlled document at www.MATS Copyright 2012, Ford Global Technolo
2、gies, LLC Page 1 of 3 COATING, CONFORMAL, SOLVENT FREE SILICONE, WSS-M99J377-A3 VERY LOW VISCOSITY NOT TO BE USED FOR NEW DESIGN 1. SCOPE The material defined by this specification is one component, primer-less, thermal curing, solvent free, silicone conformal coating. The material shall consist of
3、both vinyl and hydride functional methyl siloxane polymers, platinum catalyst, proprietary inhibitors, and adhesion promoters. A colored or UV fluorescent dye is included when specified on the Engineering Drawing. 2. APPLICATION This specification was released originally for conformal coatings used
4、for high reliability electronic assemblies. This coating is suitable for application by dip, flow, spray and brushing, and provides good wetting characteristics to a wide variety of substrates. It is intended that conformal coatings qualified to this specification be mutually compatible reducing the
5、 need for complete flushing of recirculating type coating systems during material changeover. 3. REQUIREMENTS Material specification requirements are to be used for initial qualification of materials. 3.0 STANDARD REQUIREMENTS FOR PRODUCTION MATERIALS Material suppliers and part producers must confo
6、rm to the Companys Standard Requirements For Production Materials (WSS-M99P1111-A). 3.4 APPEARANCE Bulk Liquid Translucent Cured Coating Transparent 3.5 VISCOSITY, mPa.s 190 - 300 (ASTM D 1084, Brookfield Model LVF, #3 spindle at 60 rpm) 3.6 NON-VOLATILE, min 97% (ASTM D 2369) 3.7 MECHANICAL PROPERT
7、IES 3.7.1 Sample Preparation Cast a slab of conformal coating 3 to 4 mm thick in a mold coated with a suitable non-silicone mold release. After filling the mold, allow the uncured conformal coating to stand for 1 h. Cure the conformal coating for 16 h at 50 C followed by 1 h at 105 C. ENGINEERING MA
8、TERIAL SPECIFICATION WSS-M99J377-A3 Copyright 2012, Ford Global Technologies, LLC Page 2 of 3 3.7.2 Tensile Strength, min 0.06 MPa (ASTM D 412) 3.7.3 Elongation, min 10% (ASTM D 412) 3.7.4 Hardness 30 - 50 (ASTM D 2240) (Shore A) Stack slab samples to a minimum of 15 mm prior to measuring hardness.
9、3.8 ELECTRICAL PROPERTIES 3.8.1 Dielectric Strength, min 20 kV/mm (ASTM D 149, 10 MHz) Prepare a sample slab per para 3.7.1 with the exception that the sample shall be 0.1 to 0.2 mm thick. 3.8.2 Dielectric Constant, max 3.5 (ASTM D 150, 10 MHz) Prepare a sample slab per para 3.7.1. 3.8.3 Dissipation
10、 Factor, max 0.005 (ASTM D 150, 10 MHz) Prepare a sample slab per para 3.7.1. 3.9 FUNCTIONAL PROPERTIES 3.9.1 Silicone Volatiles, max 0.5% (FLTM AV 102-01) 3.9.2 Adhesion in Shear Must fail in (ASTM D 1002, except as noted) cohesion Prepare lap shear samples using ASTM D 709, Grade FR4 unclad lamina
11、te test strips which have been cleaned in isopropanol and dried for 1 h at 105 C. After preparation, dip 25 to 40 mm length of the test strips in the uncured coating. Let the dipped test strips drip for 10 s, and then prepare the lap joint by pressing the strips together. Cure the lap joint for 30 m
12、inutes at 150 C. 3.10 DURABILITY PROPERTIES (Mil-I-46058 (latest revision), Silicone Resin (Type SR), coating thickness to as obtained in the normal manufacturing process) 3.10.1 Fungus Resistance Must meet 3.10.2 Insulation Resistance Must meet ENGINEERING MATERIAL SPECIFICATION WSS-M99J377-A3 Copy
13、right 2012, Ford Global Technologies, LLC Page 3 of 3 3.10.3 Thermal Shock Must meet 3.10.4 Moisture Resistance Must meet 3.10.5 Hydrolytic Stability Must meet 3.11 ADDITIONAL REQUIREMENTS Candidate materials shall successfully complete the following testing prior to approval to this specification.
14、Highly Accelerated Pressure Cooker test using material in the as-received and end-of-shelf-life condition. Production Shop Trial. Component/Module Life Cycle Testing as specified by the design responsible activity. Details of these tests are available from the responsible activities within the Produ
15、ct Engineering Office. 3.12 SHELF LIFE 6 months Manufacturer shall certify that the material will meet the specification when stored in the original sealed container at 35 C for the specified period. 5. GENERAL INFORMATION The information given below is provided for clarification and assistance in m
16、eeting the requirements of this specification. 5.1 COMPATIBILITY Compatibility of coating materials with substrates must be established prior to implementation. The presence of certain chemical compounds will cause inhibition of cure. Generic categories of these materials include sulfur compounds, amines, certain organometallic compounds (most commonly tin soaps), and plasticizers/mold release agents found on components. The presence of contaminants can contribute to adhesion failures when exposed to humidity and temperature cycling.
