Ultrasonic energy in conjunction with the double-diffusion treating technique

An abbreviated review of the state-of-the-art in ultrasonic enhancement of the preservation of wood through impregnation with preservative chemicals is presented. Experimental results obtained during controlled impregnation of white spruce (Picea glauca) with saturated sodium fluoride (NaF) solution indicate enhanced flow rate and retention of fluoride ion in the presence of a 47-kHz ultrasonic field after an initial induction period.