Zinc borate, well-known for its fungicidal, insecticidal and flame resistant properties, is widely used in manufacture of lignocellulose particle board. This form of borate is the least water soluble form available providing advantages as well as disadvantages for use as a wood preservative. This form does not leach from wood under conditions of high humidity, but it is also very difficult to apply evenly and within solid wood. Wood can first be micronized prior to treatment allowing access to its microstructure and allow more uniform preservation. Another option for application, described in this report, is the use of zinc ammonia borate complexes. This form, typically used as a fungicide, was found to have improved penetrability to intricacies of different wood types. An ammonia suspension 5% zinc was used to treat and impregnate specimens of Pinus taeda, Eucalyptus grandis and Populus spp. After treatment and driying, half of them were subjected to leaching tests and finally all specimens were exposed to either white rot and brown rot fungi, Coriolus versicolor and Gloeophylum trabeum, respectively, according to EN113 standard. The samples of P. taeda wood showed higher retention of mass than the hardwoods. In addition, the wood specimens were protected from the fungi despite leaching. The specimens were then examined by microscopy. Studies on the use of zinc ammonia borate complexes as preservative for solid wood continues with the monitoring of a ground bed test with specimens of Pinus taeda and Populus sp that has already been implemented.

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