Combustion properties of Rowan wood impregnated with various chemical materials
The common use of Rowan wood (Sorbus aucuparia Lipsky) in the forest products industry of Turkey, was evaluated for some of the combustion properties after impregnation with various chemical materials. For this purpose, the wood test samples prepared from Rowan wood materials according to TS 345 were treated with Tanalith-E, Vacsol-Azure, Imersol-Aqua and Boron compounds (Borax and Boric asid) by the vacuum impregnation process in accordance with ASTM D-1413 standards and directives of the manufacturer. After impregnation, each sample was tested for observation of retention amount and combustion properties (ASTM E 160-50). It has been proven that combustion properties of the impregnated Rowan wood materials were affected by impregnated materials. As a result, combustion temperature was measured as highest in Imersol Aqua (458.686°C) and the lowest in Borax (439.023°C). The impact of impregnation material decreases after the ignition and the main impact was in flame sourced combustion. In addition, boric acid reduces the material loss in combustion, ensuring that the material is more resistant to sudden collapse and destruction. As a result, it appears that impregnation of wood material with appropriate boron treatment will further increase combustion temperatures and provide additional fire resistance and a degree of security. 
 
   
 
 Key words: Rowan wood, combustion properties, Tanalith-E, Vacsol-Azure, Imersol-Aqua, Boron compounds.
Mobilya ve Ahşap Malzeme Araştırmaları Dergisi
The aim of this study was to investigate the combustion properties of Scots pine (Pinus sylvestris Lipsky) wood impregnated with boron compound (borax (Na2B4O710H2O), boric acid (H3BO3) w/w 50:50%) doped colophony (C19H29COOH). For this aim, Scots pine wood samples were impregnated with boron compound doped colophony by the method of medium-term dipping according to ASTM D 1413 and producers’ definition. Combustion properties of samples after impregnated process were determined according to ASTM E 160. As a part of the research, 6 different combination and contents of impregnation materials have been used in order to especially investigate resistance against combustion of wood material treated with boron compounds in different concentrations. Consequently, retention performance and leaching resistance of boron compounds can be increased through colophony addition. Impregnation materials with colophony decreased the flame sourced combustion (Fsc) temperatures depending on kind of impregnation material, combustion period and weight loss ratio of the test samples decreased in comparison to the control samples. Colophony can be preferred in impregnation with boron compounds depending on kind of wood and using area.
Failure analysis for poor solderability of Au surface of PCB
Nonwetting is one of the common problems and is always rejected in electronic assemblies. ENIG pads of a PCBA exhibited nonwetting after lead-free reflow soldering. With the aid of stereomicroscope, SEM&EDS and XRF, a series of analysis was performed. And after visual inspection, surface and cross section analysis, thickness measurement and solderability test, it can be inferred that oxidation of plating surface was the main reason for nonwetting, and corrosion in Ni plating caused an adverse impact on solderalibity.