Influence of Flame and Hydrofluoric Acid Treatment on Surface Damage of Tableware

Rim area is a critical part of tableware with respect to corrosion in dishwashing process and also during sensitive in organic lustre decoration. The goal of this study was to analyse influence of both process the thermal treatment and HF etching on glass surface composition. Glass samples coming from production were analysed using visual assessment, optical microscopy, Scanning Electron Microscopy (SEM) and Electron Microprobe Analysis (EMA-EDXA). Surfaces treated by flame during edge melting showed significant decrease of sodium (average 7%) and increase of organic carbon (till 71 atom %). The same locations exhibited surface damage during dishwashing and lustre decoration. The inner side of the critical surface showed only slight dealkalization (average 3%), while glass surface without secondary flame treatment did not differ incomposition from glass bulk. Surfaces etched by HF were depleted by sodium (average 30%), enriched by calcium and potassium (average 18-43 %). Also CaF₂ presence was found out as a result of crystallisation. Inspite of a different composition from a bulk, no damage was never observed after HF application during lustre decoration. Presence of organic carbon originated probably from reduction flame seems to be more important formentioned type of damage as the differences in glass compositions caused by heat treatment

The influence of selected factors on the strenght of wood adhesive joints

This paper examines the effect of selected factors on the wood bonded joint strength. The structural factor under scrutiny was the geometry of the surface area; however, other major dimensions of adherends were compared as well. The tests were per-formed on 6 joint types: butt, v-shaped, interlocking, scarf, tongue & groove, and single lap joints, which were formed on two types of substrate materials – pine and oak wood, and adhesively bonded. The joints were bonded with Prefere 6312 wood adhesive and Loctite 3430 two-component epoxy adhesive. Strength testing of the joints was performed on Zwick/Roell Z150 material testing machine, according to DIN EN 1465 standard. The results obtained from the tests indicate that bonded joints of oak wood exhibit higher strength properties than those of pine wood adherends, which was confirmed in nearly all strength tests

Friction and wear properties of nano-Si<inf>3</inf>N<inf>4</inf>/nano-SiC composite under nanolubricated conditions

Friction and wear properties of nano-Si3N4/nano-SiC composite were studied under nanolubricated conditions. Mineral oil mixed with nanoparticles of diamond was used as lubricant. A friction coefficient of 0.043 and a wear coefficient of 4.2×10-7 were obtained for nano-Si3N4/nano-SiC composite under normal load of 600 N with mineral oil + 0.5 wt% nanodiamond, whereas a friction coefficient of 0.077 and a wear coefficient of 10.3×10-7 were obtained for nano-Si3N4/nano-SiC composite under normal load of 600 N with mineral oil. 3D surface profilometer was used to study the surface morphology of wear scars. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) studies were conducted to illustrate reduction in friction and wear

Thermal analysis study of polymer-to-ceramic conversion of organosilicon precursors

The organosilicon precursors attract significant attention as substances, which upon heating in inert or reactive atmosphere convert directly to oxide or non-oxide ceramics, like nitrides, carbides, carbonitrides, boroncarbonitrides, oxycarbides, alons, etc. In characterisation, and in study of conversion of these polymers to ceramics thermal analysis plays an important role. The degree of cross-linking of the polymer vital for achievement of high ceramic yield is estimated with the use of thermal mechanical analysis (TMA). Decomposition of polymers and their conversion to ceramics is studied by the combination of differential thermal analysis (DTA), differential scanning calorimetry (DSC) thermogravimetry(TG), and mass spectrometry (MS). The use of these methods in study of the polymer-to-ceramic conversion is illustrated by case studies of a commercially available poly(allyl)carbosilane as the precursor of SiC, and a poly(hydridomethyl)silazane as the precursor of SiCN

Preface

Engineering ceramics are recently becoming more attractive and the number of various applications in industry is slightly but steadily increasing. The wider use of engineering ceramics is related to their multifunctional character which made them interesting for particular applications compared to other classes of materials. Therefore, data on catalytic, optical, electrical and/or thermal properties are important beside the typical characteristic values of the mechanical properties, such as strength, hardness or fracture resistance. The advanced research workshop Engineering Ceramics 2007 held in Smolenice Castle, Slovakia, from 6 to 10 May 2007 with the subtitle: From engineering to functionality fully confirmed this trend. The workshop was focused on recent advances in ceramic research as well as in their usage in industry. Lectures given by academics as well as researchers from industry gave insights in research on nano-ceramics, ultrahigh temperature materials and multifunctional materials. Especially contributions from industry demonstrated the high potential of multifunctional ceramic materials for applications in the automotive and engineering area. The total number of participants was restricted to 80 and allowed intensive discussions within the one session programme. Close interactions between participants were further stimulated by the relatively large number of industry people (15%), but also by the attractive ambience of Smolenice Castle. A part of the programme was dedicated to Rowland Morell Cannon, one of the best known ceramists in the world, who passed away suddenly and unexpectedly in April 2006. As a Research Engineer, Lecturer and Staff Scientist at the University of California, Berkeley and the Lawrence Berkeley National Laboratory, he engendered the respect, trust and affection from a wide network of colleagues and collaborators across the globe. R.M. Cannon participated in the past several times at our workshop on Engineering Ceramics in Smolenice Castle and made strong contributions with his profound understanding to give us new insights into the mechanical behavior and microstructure evolution in ceramics. The extraordinary impact of his research in the thermodynamics, processing and structural properties of ceramics as well as his strong personality was emphasized by Richard Brook. Further lectures covering the character, stability and properties of interfaces for ceramics and their role in microstructure development and mechanical behavior were given by former collaborators

Analysis of brake system damage in vehicles municipal communication in Lublin in the years 2011-2015

Celem artykułu jest analiza liczby uszkodzeń układu hamulcowego. Wstępnym etapem są analizy statystyczne opisujące częstotliwość pojawiania się uszkodzeń tego układu. W niniejszym artykule autorzy przedstawili wyniki takiej analizy dla wybranej grupy autobusów eksploatowanych przez Miejskie Przedsiębiorstwo Komunikacji w Lublinie. Analizę statystyczną uszkodzeń układu hamulcowego przeprowadzono w okresie od 2011 do 2015 roku dla grupy pojazdów marki Jelcz M121M.The aim of this article is to analyze the number of damage to the braking system. The preliminary stage is the statistical analysis describing the frequency of occurrence of damage of this system. In this article the authors present the results of this analysis for the selected group of buses operated by Municipal Communication Company in Lublin. A statistical analysis of damage to the braking system was carried out in the period from 2011 to 2015 for the group of vehicles Jelcz M121M

Processing and mechanical properties of Si3N4 composites employing polymer-derived SiAlOC as sintering aid

Silicon nitride ceramics have been densified with polymer-derived SiAlOC sintering aid. Dense samples were prepared at relatively mild temperatures (1600 °C) from blends with 30 wt.% of pyrolysed SiAlOC additives. Decreasing the SiAlOC aid content to 15 wt.% resulted in porous Si3N4 samples (∼85% rel. density). The properties of dense samples were influenced by the remaining SiAlOC glass (HV = 15.5 GPa, KIC = 4 MPa m1/2). Increasing the sintering temperature to 1780 °C for 5 min significantly changed the phase composition and properties of the composites. The major phase was O′-sialon in the sintered samples. Additional annealing of the samples at 1530 °C for 16 h further decreased the amount of the residual glassy phase and consequently affected the mechanical properties. The Vickers hardness of dense samples was 18.5 GPa and the fracture resistance ranged between 4.0 and 4.5 MPa m1/2. The compressive creep test (1400 °C/100 MPa/24 h) of the SNA30-A sample sintered at 1600 °C for 30 min without an additional crystallisation step showed a promising low creep rate of 8.6 × 10−8 s−1. Further improvement of creep resistance is expected for the crystallised samples