Preparation Of Hydroxide, SiC, Graphite Coatings And The Study On Their Infrared Emissivity

Hydroxide was a new kind of layered double compounds.It had been applied to drilling in the oil-field, catalyst and adsorption, water treatment, heat preservation material, and so on. But there was no reported about hydroxide application to infrared stealthy material. It had great significance to national defence to study low emissivity coatings which had low cost, construction convenience, security and combination of visible light camouflage and radar stealthy.Ni-Al-CO3 LDHs (1#) and Mg-Al-CO3 LDHs were synthesized with urea method. Succinic acid pillared layered double hydroxides were successfully synthesized by ion exchange method and one-step method with Ni-Al-CO3 LDHs(1#) precursor in the succinic acid solution .The structures of samples were characterized by XRD , IR , TG-DTA and element analysis .The emissivities of four kinds of hydroxide-coatings were studied polysulphone and inartificial rubber as the adhesive.The results show that:(1) Polysulphone and inartificial rubber were the perfect adhesives for making low emissivity coatings because the emissivities of polysulphone and inartificial rubber were 0.417 and 0.645 at 60℃4~25μm.(2) Polysulphone as the adhesive, when the content of Ni-Al-Su-acid LDHs (2#, 3#) was the same, the emissivity of coating which was made by Ni-Al-Su-acid LDHs (2#) was lower. At 60℃8～14μm polysulphone as the adhesive, the biggest emissivity of coating which was made by Ni-Al-Su-acid LDHs (2#) was 0.565, the lowest emissivity was 0.417; the biggest emissivity of coating which was made by Ni-Al-Su-acid LDHs (3#) was 0.621,the lowest emissivity was 0.417.(3) At 60℃8～14μm polysulphone as the adhesive, the biggest emissivity of coating which was made by Mg-Al-CO3 LDHs was 0.598,the lowest emissivity was 0.417 ; Phenolic anti-rusting paint was at the bottom inartificial rubber as the adhesive, the biggest emissivity of coating which was made by Mg-Al-CO3 LDHs was 0.645,the lowest emissivity was 0.570.(4) At 60℃8～14μm polysulphone as the adhesive, the biggest emissivity of coating which was made by Ni-Al-CO3 LDHs(1#) was 0.633,the lowest emissivity was 0.417 ; Phenolic anti-rusting paint was at the bottom inartificial rubber as the adhesive, the biggest emissivity of coating which was made by Ni-Al-CO3 LDHs(1#)was 0.645,the lowest emissivity was 0.620. At the same time, the emissivities of SiC and graphite coatings were studied inartificial rubber as the adhesive.The results show that:(5) At 60℃8～14μm phenolic anti-rusting paint was at the bottom inartificial rubber as the adhesive, the biggest emissivity of coating which was made by SiC was 0.645,the lowest emissivity was 0.580.(6) At 60℃8～14μm phenolic anti-rusting paint was at the bottom inartificial rubber as the adhesive, the biggest emissivity of coating which was made by graphite was 0.645,the lowest emissivity was 0.500.Hydroxide had layered double structure, the infrared wave absorbed by its coating was consumed because of electron diffraction, dispersivity, electron transition or crystal disfigurement, or was reflected from different direction.So coating emissivity was lower.