Damage of aluminum samples with alumina ceramic coating under pulsed energy flows of various nature
The damageability of alumina ceramic coating on the aluminum substrate under the inluence of concentrated energy luxes of diferent nature and pulse duration have been investigated. Laser radiation in the free-running mod (with pMower density q = 10<sup>5 </sup><sup>- </sup>2·10<sup>6</sup> W/cm<sup>2</sup> and pulse duration τ <sup>= </sup>0.7 ms) and the Q-switched mod ( <sup>q </sup><sup>=</sup> 10<sup>7</sup> - 10<sup>8</sup> W / cm<sup>2</sup><sup>, </sup><sup>τ</sup> = 80 ns), as well as beam-plasma efects at q = 10<sup>7 </sup>- 10<sup>9</sup> W/cm<sup>2</sup>, τ = 50 - 100 ns were used as pulsed heat load. It is shown that under action of millisecond and nanosecond pulsed laser radiation on the semitransparent ceramic coating its damage is caused by the partial destruction and peeling of the ceramic layer from the metal substrate. The mechanisms of observed damageability are determined. The threshold laser radiation lux density at which the coating is damaged by the peeling mechanism have been experimentally estimated. The temperature distribution in the surface layer of the samples have been calculated by numerical simulation and it have been shown that the temperature reaches the maximum values at a depth corresponding to the contact area between the coating and the substrate. It has been established that exposure to aluminum samples with a ceramic coating of fast deuterium ion luxes and high-temperature deuterium plasma in the plasma focus device results in melting and partial evaporation of the surface coating layer.