AZ-93 is an inorganic white thermal control paint developed for use on spacecraft / satellite surfaces exposed to the deleterious effects of the space environment. Application of AZ-93 creates a nonspecular white coating that provides superior thermal control / protection by allowing only 13-17% of the solar radiation impinging on the spacecraft external surface to be absorbed through to the interior systems while emitting 89-93% of the internal heat generated to the cold vacuum of space. By incorporating a highly stabilized pigment system with a silicate binder, this spacecraft / satellite paint forms a bendable ceramic coating that has been tested time and again and has proven itself stable in the harshness of the space environment. AZ-93 has been exposed by NASA to atomic oxygen (AO) fluence of 5.6 x 1022 atoms/cm2, charged particle radiation of 4.5 x 1015 e–/cm2, and vacuum ultraviolet (VUV) radiation (from 118 nm to 170 nm) of 701 equivalent solar hours with less than 4% deterioration in solar absorptance (α_s) and less than 1% change in thermal emittance (ε_t).
AZ-93 has been thoroughly tested and is currently being used on external surfaces of the International Space Station in many capacities including on all NASA logos (see image left). A pre-cursor to AZ-93 was flown on the Long Duration Exposure Facility (LDEF) and returned after 5.8 years in orbit with only a 0.01 overall degradation in solar absorptance from pre-flight measurements. AZ-93 was flown on the Optical Properties Monitor (OPM), the MIR MEEP POSA-I experiment and the Materials International Space Station Experiment (MISSE). AZ-93 has been used on the surface of the International Space Station for more than 10 years.
The main advantage AZ-93 has over AZW/LA-II is cost. AZW/LA-II is more expensive but has extremely low solar absorptance.
The table below lists the optical and application parameters of cured AZ-93.
|Nominal Surface Resistivity||N/A|
|Thermal Emittance (ε_t)||0.91 ± 0.02|
|Solar Absorptance (α_s)||0.15 ± 0.02 at ≥ 5.0 mils thickness|
|Use Temperature Range||-180 C to 1400 C|
|Nominal Dry Thickness||5.0 ± 1.5 mils (over 85% of coated area)|
|ASTM D3359A Adhesion Grade||Not less than 3A|
|Full Cure||7 days|
|Coating coverage estimates can be found here.|
|The SDS can be found here.|
Note: terms reflectance, emittance and absorptance and terms reflectivity, emissivity and absorptivity are often used interchangeably. AZ version of Z-93P. We feel it has advantages in application Z-93.