Lubricity effect of carbon dioxide used as an environmentally friendly refrigerant in air-conditioning and refrigeration compressors

▶ Superlubricity of carbon dioxide used as a natural and environmentally friendly refrigerant. ▶ Application is for future air-conditioning and refrigeration compressors. ▶ Experiments under realistic compressor conditions using cast iron and steel samples. ▶ Superlubricity due to partial transformation of iron oxides into iron carbonates.