Zinc Borophosphate Research Articles

Study of potassium–zinc borophosphate glasses

Potassium–zinc borophosphate glasses were prepared and studied in two compositional series xK 2O–(50− x)ZnO–10B 2O 3–40P 2O 5 and xK 2O–(50− x)ZnO–20B 2O 3–30P 2O 5 with x=0, 10, 20, 30, 40 and 50 mol% K 2O. The replacement of zinc by potassium decreases the density and increases the molar volume of these glasses, whereas glass transition temperature and chemical durability decrease with increasing potassium content. Structural changes were studied by 11B and 31P MAS NMR and Raman spectroscopy. The observed changes in the spectra and the properties of the studied glasses can be ascribed to several reasons and namely to the differences in the space occupied by cations Zn 2+ and 2K +, the differences in the electronegativity of zinc and potassium and a large difference in the field strength of Zn 2+ and K + cations and thus higher ionicity of K–O bonds in comparison with Zn–O bonds.

Study of lithium–zinc borophosphate glasses

Mixed lithium–zinc borophosphate glasses were prepared and studied in three compositional series xLi2O–(50−x)ZnO–50P2O5, xLi2O–(50−x)ZnO–10B2O3–40P2O5 and xLi2O–(50−x)ZnO–20B2O3–30P2O5 with x = 0, 10, 20, 30, 40 and 50 mol% Li2O. The obtained glasses were characterized by the measurements of the density (ρ), molar volume (VM), glass transition temperature (Tg) and thermal expansion coefficient (α). For the investigation of structural changes 11B and 31P MAS NMR and Raman spectroscopy were applied. The replacement of zinc by lithium in borophosphate glasses slightly decreases VM and Tg, while α increases. In Li–Zn metaphosphate glasses the compositional dependence of Tg reveals a minimum, while at the borophosphate series Tg decreases monotonously with increasing Li2O content. Chemical stability of Li–Zn borophosphate glasses is very good for glasses with x = 0–30 mol% Li2O. Spectral studies showed in the glass series with 10 mol% B2O3 only the presence of BO4 sites. In the glasses with 20 mol% B2O3 the presence of BO3 and two BO4 sites was revealed in ZnO-rich glasses and only one BO4 site in Li2O-rich glasses; the number of BO3 groups decreases with increasing Li2O content which is ascribed to the formation of P–O–Zn covalent bonds in ZnO-rich glasses.

Thermal behaviour and crystallization of titanium–zinc borophosphate glasses

Thermal behaviour of the glass series (100–y)[0.5ZnO·0.1B2O3·0.4P2O5]·yTiO2 (with y=0–39 mol% TiO2) was investigated by DSC and TMA. The addition of TiO2 results in a non-linear increase of glass transition temperature. The compositional dependences of thermal stability, evaluated by two criteria exhibit two maxima for the glasses doped with 10.7 and 35.9 mol% TiO2. All the glasses crystallize on heating in the temperature range of 576–670°C. The crystallization mechanism was studied at the glasses with 19.4 and 35.9 mol% TiO2 and the results showed that surface nucleation mechanism prevails in these glasses over the internal one.

Structure and properties of titanium–zinc borophosphate glasses

The structure of 50ZnO–10B 2O 3–40P 2O 5+ xTiO 2 glasses prepared by slow cooling (for x=0–24 mol% TiO 2) or by quenching (for x=28–64 mol% TiO 2) was studied by Raman, 31P and 11B MAS NMR spectroscopy. TiO 2 incorporates into the glass structure, which results in a decrease in the molar volume and an increase in the glass transition temperature. According to Raman spectra Ti atoms form distorted TiO 6 octahedra and their incorporation into the structural network results in the depolymerization of phosphate chains. 11B NMR spectra of the glasses with increasing TiO 2 content show gradual changes from one symmetrical signal of B(OP) 4 units to a broad complex signal which was separated into five signals ascribed to four different types of BO 4 units and one BO 3 unit. With increasing TiO 2 content a part of boron atoms changes from tetrahedral BO 4 to trigonal BO 3 units, which is ascribed to the formation of TiO 6 units in the glass structure.

Second Harmonic Generation Induced by Poling in Zinc Borophosphate Glasses

In the development of high bit-rate capacity in telecom systems, fiber technology and/or integrated glass waveguides provide a means to implement low cost active optical devices with low insertion losses and fiber compatibility. Presently glass-based devices are limited in efficiency and it is of the utmost importance to increase the non linear optical response. In this context the present investigation compares the induced second-order optical nonlinearity generated after electro-thermal poling process in a series of borophosphate glasses of molar compositions 0.3[(0.9 - x) Ca(PO3)2–x Zn(PO3)2–0.1 CaB4O7]–0.3 Nb2O5 (x = 0–0.4). The mechanisms involved are tentatively explored.

Friction‐induced two‐dimensional solid films from lubricant additives

AbstractTribochemical interactions between some lubricant additives, namely zinc dithiophosphate (ZnDTP), an antiwear additive, molybdenum dithiocarbamate (MoDTC), a friction modifier, and overbased calcium borate (OCaB) detergent, have been investigated. The nature of the tribofilms formed was studied by combining high‐resolution transmission electron microscopy of wear fragments and inside wear scars with micro‐spot X‐ray photoelectron spectroscopy at the same location of the wear track (‘dual’ analysis).The OCaB/ZnDTP/MoDTC ternary system provides both a low wear rate and ultralow friction, while adding detergent and anti‐corrosion properties to the formulation. The analytical data indicate that such a synergistic effect can be attributed to an outstanding feature of the tribofilm nanostructure: it is composed of perfectly oriented MoS2 single sheets embedded in a single‐phase calcium and zinc borophosphate glass. Compared to phosphate alone, MoS2 sheets are oriented by the borophosphate phase. This could be related to a template effect of friction‐aligned planar molecules of the glassy borate polymer.

Crystal Growth of Magnesium Zinc Borophosphate

Abstract Single crystal of solid solution magnesium zinc borophosphate was first grown by the Czochralski method. The crystal obtained shows thick plate-like morphology with sizes up to 20 mm×15 mm×7 mm. The crystal is transparent in the wavelength range of 200–2500 nm, with the UV absorption edge at about 200 nm. The powder second harmonic generation effect of the crystal is similar to that of KH2PO4.

Tribochemical interactions between Zndtp, Modtc and calcium borate

Tribochemical interactions between antiwear zinc dithiophosphate (Zndtp), friction modifier molybdenum dithiocarbamate (Modtc) and overbased detergent calcium borate (OCB) lubricant additives have been investigated. Friction tests were performed in mild wear conditions under boundary lubrication, in order to enhance tribochemical surface effects. The nature of tribofilms formed was studied by coupling high‐resolution TEM on wear fragments and inside‐wear‐scar, micro‐spot XPS in the same location of the wear track (so‐called dual analysis). The performance of the Modtc/Zndtp mixture is mainly due to the generation of MoS2 single sheets and the digestion of MoO3 in the zinc polyphosphate glass formed. The final result of the tribochemical reaction is a two‐phase tribofilm composed of (i) non‐oriented MoS2 sheets (friction modifier) embedded in a carbon‐rich phase and (ii) a mixed Zn/Mo polyphosphate glass (antiwear). The Modtc/OCB mixture has a similar antiwear mechanism except that the oxide is not completely eliminated, due to the softer action of borate anion compared with phosphate one. Compared to the data obtained with binary combinations (Modtc/Zndtp, Modtc/OCB and Zndtp/OCB), we show here that the ternary system Modtc/Zndtp/OCB provides both a low wear rate and an ultralow friction value, while adding detergent and anti‐corrosive properties to the formulation. Our analytical data indicate that the synergistic effect can be attributed to an outstanding nanostructure of the tribofilm formed. It is composed of a single‐phase material containing perfectly oriented MoS2 single sheets embedded in a calcium and zinc borophosphate glass. The ternary system produces a smart material in the interface, because both functions (antiwear and friction reduction) are correlated. Compared to phosphate alone, the mechanism by which MoS2 sheets have been oriented in the borophosphate could be related to aligned molecules of the glassy polymer in the direction of sliding.

A dual‐analysis approach in tribochemistry: application to ZDDP/calcium borate additive interactions

Tribochemical interactions between zinc dithiophosphate (ZDDP) and micellar calcium borate (CB) under boundary lubrication were investigated by coupling, in the same location of the wear track, both analytical TEM analysis of collected wear fragments from the tribofilm and XPS surface analysis of the tribofilm directly underneath. This is the so‐called dual‐analysis approach, which improves the interpretation of tribochemical reactions. The elemental composition inside the wear scars was analysed by micro‐spot XPS. By depth profiling, the film thickness could also be determined. In particular, the efficiency of the additive combination could be proven by quantification of iron oxide. The nature of wear particles was investigated in the TEM by using EELS and EDX simultaneously, with the result that phosphorus, boron and sulphur contributions have been carefully distinguished. The technique is very powerful for determining the composition of the material through quantification of both EELS and EDX spectra on the same specimen. The main result, when ZDDP and CB additives are used together, is the formation of a calcium and zinc borophosphate glass tribofilm. The overall data confirm the general friction‐induced glass model as being a unifying concept that explains the mechanisms of antiwear additives under boundary lubrication. Moreover, the analytical results strongly suggest the role of viscous flow of the magma state glass tribofilm above its glass transition temperature to be a main contribution to the antiwear mechanism under mild wear conditions.

Structural design of sealing glasses

Requirements for enhanced component performance and reliability have led to the development of novel glass compositions for a variety of hermetic sealing applications. The development of technologically useful glass compositions was based on an understanding of the relationships between the molecular-level glass structure and important physical properties. The properties of the alkaline earth aluminoborate glasses for lithium batteries are sensitive to changes in B- and Al-coordination number, characterized by solid state nuclear magnetic resonance (NMR) spectroscopy. In general, the most useful compositions have structures that are dominated by tetrahedral B- and Al-sites. Mixed alkali aluminophosphate glasses were developed for aluminum electrical connectors. The properties of sodium aluminophosphate glasses depend on the O P ratio and significant property changes (e.g. maxima in T g and refractive index) occur when O P exceeds pyrophosphate limit at 3.5. Associated with these property changes is a decrease in the average Al-coordination number, from six to four, at O P > 3.5 . Raman spectroscopy provides additional information about the aluminophosphate network. Finally, zinc borophosphate glasses are developed for seals in flat panel displays. Boron-11 NMR shows that tetrahedral borons are preferred in xB 2O 3(1 - x)(PO 3) 2) and in yB 2O 3(1 - y)Zn 2P 2O 7 glasses for x < 0.4 and y < 0.2. Raman spectroscopy reveals the concomitant evolution from a phosphate to a borophosphate network with increasing x and y.

An XPS study of oxygen bonding in zinc phosphate and zinc borophosphate glasses

X-ray photoelectron spectroscopy has been used to determine oxygen bonding in a series of xZnO · (1 − x)P2O5 (0.50 ≤ x ≤ 0.67) glasses. Curve fitting of the O 1s spectra leads to a quantitative measure of the bridging-to-non-bridging oxygen ratio which is shown to depend on composition according to a simple structural depolymerization model. A third peak, present in the O 1s spectra collected from yB2O3 · (1 − y)Zn(PO3)2 (0.00 ≤ y ≤ 0.40) glasses, is due to oxygens which link borate and phosphate tetrahedra. The relative concentrations of POP, POZn and POB bonds are shown to be in good agreement with a structural model which assumes that borophosphate units (BPO4) form when B2O3 is added to Zn metaphosphate glass.

Zinc Borophosphate Glass

Journal of the American Ceramic SocietyVolume 47, Issue 9 p. 471-471 Zinc Borophosphate Glass D. O. GROSSMAN, D. O. GROSSMAN International Lead and Zinc Research Organization under a contract concerning the fundamental study of zinc compounds in glasses.Search for more papers by this authorC. J. PHILLIPS, C. J. PHILLIPS International Lead and Zinc Research Organization under a contract concerning the fundamental study of zinc compounds in glasses.Search for more papers by this author D. O. GROSSMAN, D. O. GROSSMAN International Lead and Zinc Research Organization under a contract concerning the fundamental study of zinc compounds in glasses.Search for more papers by this authorC. J. PHILLIPS, C. J. PHILLIPS International Lead and Zinc Research Organization under a contract concerning the fundamental study of zinc compounds in glasses.Search for more papers by this author First published: September 1964 https://doi.org/10.1111/j.1151-2916.1964.tb14443.xCitations: 10 The writers are, respectively, graduate research assistant and professor of ceramics, College of Engineering, School of Ceramics, Rutgers, The State University, New Brunswick, New Jersey. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume47, Issue9September 1964Pages 471-471 RelatedInformation