Non-Conventional Route to Glass-Ceramics for Electronic Packaging

1986 ◽  
Vol 72 ◽  
Author(s):  
C. Gensse ◽  
U. Chowdhry
Keyword(s):  
Viscous Flow ◽  
Electronic Packaging ◽  
Low Temperatures ◽  
Glass Ceramics ◽  
Fine Grained ◽  
Amorphous Powders ◽  
Organometallic Precursors

AbstractThis paper describes a non-conventional route to formation of dense glass-ceramics at relatively low temperatures. Organometallic precursors were used to synthesize powders with controlled purity and stoichiometry in the MgO/A12O3/SiO2 system. These amorphous powders sintered by viscous flow to form a dense glass below 1000°C. Further heating resulted in the formation of very fine grained glass-ceramics. Beta-quartz, cordierite, and cordierite-mullite glass-ceramics were obtained with attractive properties for electronic packaging.

Non-Conventional Route To Glass-Ceramics For Electronic Packaging

1986 ◽  
Vol 73 ◽  
Author(s):  
C. Gensse ◽  
U. Chowdhry
Keyword(s):  
Viscous Flow ◽  
Electronic Packaging ◽  
Low Temperatures ◽  
Glass Ceramics ◽  
Fine Grained ◽  
Amorphous Powders ◽  
Organometallic Precursors

ABSTRACTThis paper describes a non-conventional route to formation of dense glass-ceramics at relatively low temperatures. Organometallic precursors were used to synthesize powders with controlled purity and stoichiometry in the MgO/Al2 O3 /SiO2 system. These amorphous powders sintered by viscous flow to form a dense glass below 1000°C. Further heating resulted in the formation of very fine grained glass-ceramics. Beta-quartz, cordierite, and cordierite-mullite glass-ceramics were obtained with attractive properties for electronic packaging.

Metal Alkoxide Synthesis of Glasses and Glass-Ceramics

1985 ◽  
Vol 57 ◽  
Author(s):  
Charles H. Drummond
Keyword(s):  
Hot Pressing ◽  
Low Temperatures ◽  
Glass Formation ◽  
Glass Ceramics ◽  
Base Hydrolysis ◽  
Metal Alkoxide ◽  
Metal Alkoxides ◽  
Fine Grained ◽  
Amorphous Powders

AbstractMetal alkoxide syntheses of the general form or can be used to form soluble alkoxides of most metals. Mutual solution of these alkoxides followed by acid or base hydrolysis, drying and calcining results in the formation of fine-grained (<10Å) amorphous powders at low temperatures. Subsequent hot-pressing or calcining leads to densification and/or crystallization. Compositions in the MgO-Al2O3-SiO2 system with ZrO2 contents to 30 mol% are discussed. Also glass formation of transition oxides derived from metal alkoxides of Hf, Zr, Y and Nb in various combinations are presented.

scholarly journals Use of Fine-Grained Heat-Strengthened Steels to Increase the Operation Qualities of Bunker Capacities from Thin-Walled Galvanized Profiles

2021 ◽  
pp. 84-93
Author(s):  
Y. I. Hezentsvei ◽  
D. O. Bannikov
Keyword(s):  
Low Temperatures ◽  
High Strength Steels ◽  
High Strength ◽  
Numerical Calculations ◽  
Structural Scheme ◽  
Plan View ◽  
Fine Grained ◽  
Steel Sheets ◽  
Stiffening Ribs ◽  
Corrugated Sheets

Purpose. The work is aimed to study the use efficiency of fine-grained heat-strengthened steels (mainly 10G2FB) for steel bunker capacities. At the same time, the structural scheme of such a structure using corrugated steel sheets is considered as the main variant. Methodology. To achieve this purpose, a series of numerical calculations was carried out for a steel bunker capacity of a pyramidal-prismatic type with overall dimensions in plan view of 6×5.2 m and a total height of 4.5 m. The capacity was designed for complicated working conditions, in particular, increased loads, including long-term dynamic ones. The potential possibility of operating the container under conditions of high or low temperatures was also taken into account. At the same time, both the traditional structural scheme of a bunker capacity with horizontal stiffening ribs and the developed structural scheme based on corrugated steel sheets were analyzed. The calculations were carried out by the finite element method based on the SCAD for Windows project complex. Findings. Based on the results of the analysis and comparison of the data obtained in numerical calculations, it was found that the use of fine-grained heat-strengthened high-strength steels (for example, steel 10G2FB) for bunker capacities, both the traditional structural scheme with stiffening ribs and the developed structural scheme based on corrugated sheets, allows reducing material consumption by about 30% in both cases. At the same time, due to the good performance of fine-grained heat-strengthened steel 10G2FB, both at high and at low temperatures, it can be effectively used for steel bunker capacities that work in difficult conditions. Originality. The possibility and efficiency of the use of fine-grained, heat-strengthened high-strength steels for the construction of a steel bunker capacity is estimated. At the same time, such an estimation was given not only for structures of the traditional structural scheme with horizontal stiffening ribs, but also for bunkers with a developed structural scheme based on corrugated sheets. Practical value. From a practical point of view, quantitative parameters of the stress-strain state were obtained during investigations of various design variants for a steel bunker capacity. The data are presented in a compact form that is easy to evaluate and compare. They allow us to state about the improvement of the operation characteristics of capacities and the potential reduction of the risks of their failures and accidents during operation.

From Nanocomposite Aerogels to Glass Ceramics for Nuclear Wastes Containment

2011 ◽  
Vol 172-174 ◽  
pp. 791-796 ◽  
Author(s):  
Thierry Woignier ◽  
Jerome Reynes ◽  
Sylvie Calas
Keyword(s):  
Viscous Flow ◽  
Thermal Shock ◽  
Nuclear Waste ◽  
High Resistance ◽  
Solid Phase ◽  
Glass Ceramics ◽  
Chemical Species ◽  
Host Matrix ◽  
Waste Containment ◽  
Two Phases

Nanocomposite aerogel is proposed as a host matrix for the synthesis of glass ceramics. The large porosity is used as a sponge to incorporate chemical species getting a two phases material. We describe the steps of the synthesis of glass ceramics for nuclear waste containment, from nanocomposite aerogels loaded with actinides surrogates (Ce and Nd). The glass synthesis is obtained without melting, by a control of several solid phase transformations: sintering, viscous flow, crystallization and foaming. Thanks to their high resistance to thermal shock and water corrosion, these glass ceramics are certainly good candidates as actinides containment materials.

scholarly journals Superplasticity and Newtonian-viscous flow in fine-grained class I solid solution alloys.

1991 ◽  
Vol 31 (1) ◽  
pp. 76-85 ◽  
Author(s):  
H. Fukuyo ◽  
H. C. Tsai ◽  
T. Oyama ◽  
O. D. Sherby
Keyword(s):  
Solid Solution ◽  
Viscous Flow ◽  
Class I ◽  
Fine Grained

Ceramic Materials for Electronic Packaging

1989 ◽  
Vol 111 (3) ◽  
pp. 183-191 ◽  
Author(s):  
E. M. Rabinovich
Keyword(s):  
Electronic Packaging ◽  
Sol Gel ◽  
Glass Ceramics ◽  
Ceramic Materials ◽  
Packaging Materials ◽  
Ceramic Powders ◽  
Main Attention

The paper reviews ceramic materials that are used or can be used in electronic packaging. Main attention is given in relatively new packaging materials such as highly thermal conductive AlN and SiC (BeO-doped) or low-firing cordierite and spodumene glass-ceramics. Application of sol-gel processes in preparation of ceramic powders is discussed.

Thick-Film Processing of Pb5Ge3O11-Based Ferroelectric Glass-Ceramics

1995 ◽  
Vol 398 ◽  
Author(s):  
Iván A. Cornejo ◽  
Michael J. Haun
Keyword(s):  
Thick Film ◽  
Glass Ceramic ◽  
Low Temperatures ◽  
Ferroelectric Phase ◽  
Glass Ceramics ◽  
Axis Orientation ◽  
Film Processing ◽  
Processing Techniques

ABSTRACTProcessing techniques were investigated to produce c-axis orientation, or texture, of ferroelectric Pb5Ge3O11-based glass-ceramic compositions during crystallization of amorphous thick-film printed samples from the Pb5Ge3O11-PbTiO3 (PG-PT) and Pb5Ge3O11Pb(Zr1/2Ti1/2)O3 (PG-PZT) systems. In these systems the PG crystallized into a ferroelectric phase, producing a multiple ferroelectric phase composite at low temperatures, PG-PT or PG-PZT. In this way the non-ferroelectric component of traditional ferroelectric glass-ceramics was eliminated.

Some recent developments in high-strength glasses and ceramics

1964 ◽  
Vol 282 (1388) ◽  
pp. 52-56
Keyword(s):  
Thermal Expansion ◽  
Bending Strength ◽  
Glass Ceramics ◽  
High Strength ◽  
Fine Grained ◽  
Thermal Expansion Coefficients ◽  
Low Thermal Expansion ◽  
Recent Developments ◽  
Expansion Coefficients ◽  
Mechanical Strengths

Two areas of development in the field of glasses and ceramics have produced new materials with unusual combinations of properties. Glass-ceramics are melted and formed as glasses by conventional glass-forming techniques, but by a subsequent heat treatment, they are converted to fine-grained crystalline structures with new and useful combinations of properties. Products with thermal expansion coefficients approaching zero and flexural strengths ranging from 10 000 to 50 000 Lb./in. 2 have been made though not all combinations of low thermal expansion coefficients and high mechanical strengths are possible. The second area of development is in so-called Chemcor glasses. Such glass products can be preferentially pre-stressed by chemical means so as to produce an outer layer with high compressive stress and a bending strength in the finished product up to 100 000 Lb/in. 2 .

Gel-derived amorphous cesium-aluminosilicate powders useful for formation of pollucite glass-ceramics

1991 ◽  
Vol 6 (2) ◽  
pp. 217-219 ◽  
Author(s):  
Mari A. Hogan ◽  
Subhash H. Risbud
Keyword(s):  
Electron Microscopy ◽  
Sol Gel ◽  
Glass Ceramics ◽  
Amorphous Powder ◽  
Glass Crystallization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Amorphous Powders ◽  
Gel Processing ◽  
Scanning Electron

Amorphous powders in the Cs2O–Al2O3−SiO2 system were prepared by sol-gel processing. Gels made from TEOS, Al-chelate, and Cs-acetate were dried and calcined to obtain molecularly mixed powders of analyzed compositions in the range useful for conversion to pollucite (CsAlSi2O6) glass-ceramics. X-ray diffraction (XRD), differential thermal analysis (DTA), thermogravimetry (TG), and scanning electron microscopy (SEM) were used to characterize the powders. A typical amorphous powder of analyzed chemical composition (in wt.%) = 28.05Cs2O, 37.77SiO2, and 37.96Al2O3 was found to have a glass transition temperature of 945 °C and a glass crystallization temperature of 1026 °C. Preliminary experimental results of densification and crystallization of the amorphous powders show pollucite/mullite phases to be present.

scholarly journals Characterisation and Properties of Lithium Disilicate Glass Ceramics in the SiO2-Li2O-K2O-Al2O3System for Dental Applications

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Naruporn Monmaturapoj ◽  
Pornchanok Lawita ◽  
Witoon Thepsuwan
Keyword(s):  
Glass Composition ◽  
Glass Ceramics ◽  
Lithium Disilicate ◽  
Nucleating Agents ◽  
Fine Grained ◽  
Melting Glass ◽  
Heterogenous Nucleation ◽  
Dental Applications ◽  
Slight Amount ◽  
Glass Compositions

This work proposes four different glass formulas derived from the SiO2-Li2O-K2O-Al2O3system to investigate the effect of glass composition on their crystal formations and properties. Glass LD1 was SiO2-Li2O-K2O-Al2O3system with the addition of P2O5and CaF2as nucleating agents. In Glass LD2, a slight amount of MgO was mixed in order to increase the viscosity of the melting glass. Finally, the important factor of Si : Li ratio was increased in Glasses LD3 and LD4 with compositions otherwise the same as LD1 and LD2. The results found that P2O5and CaF2served as a nucleating site for lithium phosphate and fluorapatite to encourage heterogenous nucleation and produce a fine-grained interlocking microstructure of lithium disilicate glass ceramics. MgO content in this system seemed to increase the viscosity of the melting glass and thermal expansion coefficient including the chemical solubility. Increasing the Si : Li ratio in glass compositions resulted in the change of the microstructure of Li2Si2O5crystals.

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