Cooling erosion protection

Ablation means removal of material from the surface of an object by vaporization, chipping, or other erosive processes. The term occurs in Space Physics [5]. In space vehicle design, ablation is used to both cool and protect mechanical parts and/or payloads that would otherwise be damaged by extremely high temperatures. A low-density EPDM rubber is a fire stopping and fire proofing product that can be ablative in nature. 

Y. Gudimenko, Z. Iskanderova, J. Kleiman, G. Cool, D. Morison and R. Tennyson, Erosion Protection of Polymer Materials in Spaice, 7th International Symposium on Materials in a Space Environment, held in Tolouse, France, 16-20 June 1997, ESA Special Publication 399, Ed. T. D. Guyenne (European Space Agency, Paris, Prance, 1997) pp. 403-410. 

Metal surfaces in a well-designed, well-operated cooling water system will establish an equilibrium with the environment by forming a coating of protective corrosion product. This covering effectively isolates the metal from the environment, thereby stifling additional corrosion. Any mechanical, chemical, or chemical and mechanical condition that affects the ability of the metal to form and maintain this protective coating can lead to metal deterioration. Erosion-corrosion is a classic example of a chemical and mechanical condition of this type. A typical sequence of events is ... 

Metals that depend on a relatively thick protective coating of corrosion product for corrosion resistance are frequently subject to erosion-corrosion. This is due to the poor adherence of these coatings relative to the thin films formed by the classical passive metals, such as stainless steel and titanium. Both stainless steel and titanium are relatively immune to erosion-corrosion in most cooling water environments. 

This inherent property reduces the amormt of heat treating and postmachining. 6B has outstanding resistance to cavitation erosion. Steam turbine erosion shields fiem 6B have protected the blades of turbines for years of continuous service. 6B has good impact and thermal shock resistance, resists heat and oxidation, retains high hardness even at red heat (when cooled, recovers ffill original hardness), and has resistance to a variety of corrosive media. 6B is useftd where both wear and corrosion resistance are needed. 

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