Computer-aided glass composition design apparatus and method
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation-in-part of application Ser. No. 07/314,075, which was filed on Feb. 23, 1989 and which is now abandoned. 
     INVENTOR 
     Akio MAKISHIMA 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an apparatus and method in support of glass design. More particularly, the present invention relates to a computer aided glass composition design apparatus used in the selection and design of a composite of vitrifying multielement composite oxides and various physical property values of glass materials. 
     2. Description of the Prior Art 
     Materials known as &#34;new glass&#34; having properties which are different from those of conventional glass materials are now attracting widespread attention, and various types of glass materials falling into the &#34;new glass&#34; category have been developed. As typically represented by glass materials used for optical fibers, these materials now play an important role in supporting the present information age. As with other ceramic materials, glass materials having utilities which are quite different from those of the conventional glass materials are being studied for use in optoelectronic, electrical and electronic, and biological and biochemical fields. 
     However, since these new glass materials are composite compositions comprising many compounds, particularly many oxides, it is not easy to achieve desired physical properties by precisely controlling their composition. 
     It is therefore necessary to accumulate experimental findings through innumerable trials and utilize such findings in the development of the new glass materials. The selection of raw material compositions and component ratios thus entails substantial time and labor. 
     It has therefore been very difficult to practically achieve a glass composition having desired prescribed physical properties. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is therefore to provide an apparatus for support of glass design, which overcomes the conventional problems of substantial time and labor consumption and which facilitates the design of a glass material having a desired composition or utility, permitting efficient selection of a composition of vitrifying multielement composite oxides and selection of physical properties. 
     This and other objects of the present invention will be readily understood from the following detailed description with reference to the drawings illustrating embodiments of the present invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a block diagram illustrating a configuration of the present invention; 
     FIG. 2 is a system flow chart of an embodiment of the apparatus of the present invention; 
     FIGS. 3, 4 and 5 are views illustrating examples of a display in accordance with the flow chart shown in FIG. 2; 
     FIG. 6 is a system flow chart of another embodiment of the present invention; 
     FIGS. 7, 8, 9 and 10 are views illustrating examples of a display in accordance with the flow chart shown in FIG. 6; and 
     FIGS. 11 and 12 are graphs depicting calculated and measured properties of example glass materials manufactured in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     The embodiments of the present invention are described below with reference to the drawings. 
     FIG. 1 is a block diagram illustrating a configuration of the computer-aided glass composition design apparatus of the present invention. As shown in FIG. 1, the apparatus includes a memory unit (1) such as a RAM or ROM, an input unit (2) such as a keyboard or a mouse, a calculating unit (3) and a comparator (4) such as a processor, and a display unit (5) such as a CRT. The memory unit (1) has stored therein a list of glass component compounds, glass compositions and glass physical properties. Data information from this list is directed to the input unit (2), the calculating unit (3) and the comparator (4). 
     The display unit (5) may be of the interactive type and may be provided with input functions. 
     The operation of the computer-aided glass composition design apparatus of the above configuration is described below with further reference to FIGS. 2-5. 
     A desired composition (including component ratios) is selected from the list of component compounds displayed on the display unit (5), and the selected composition is entered via the input unit (2). For example, as shown in FIG. 3, in the case of oxides as component compounds, a desired composition of oxides is selected from the displayed list and entered by operation of the input unit (2), for example using a mouse. 
     After the completion of this initial input process, values of physical properties corresponding to the selected composition are calculated by the calculating unit (3). In the preferred embodiment, the value of only a single representative or particularly important physical property is first calculated. Then, after determining the appropriateness of the value of this single property, using the comparator (4) as described below, other physical property values may be calculated. 
     In the example shown in FIG. 2, Young&#39;s modulus is adopted as the representative or particularly important physical property value. Young&#39;s modulus is calculated from the selected combination of oxides. Young&#39;s modulus is adopted here because particular attention is given to the glass modulus of elasticity. The composition ratio and the calculated Young&#39;s modulus is displayed as shown in FIG. 4. 
     Young&#39;s modulus in this example is calculated as 676.101 kbar, which is judged to be rather low as a glass property. The comparator (4) compares the calculated value of Young&#39;s modulus with a prestored value range of Young&#39;s modulus. The prestored value range may, for example, denote values in which vitrification of the entered composition is feasible. If the calculated Young&#39;s modulus falls outside the prestored value range, the comparator (4) prompts the display (5) to so indicate, for example, as shown in FIG. 4. When the value of Young&#39;s modulus is too low or too high, a corrected composition is entered again via the input unit (2). 
     When appropriate, calculation is further performed for the other physical properties as discussed above. That is, for example, when comparator (4) determines that the calculated Young&#39;s modulus value falls within the prestored range, the other physical properties of the entered composition may be calculated and displayed. 
     FIG. 5 shows a typical display of calculated values of other physical properties. When these calculated values of physical properties are different from those desired of the target glass material, another glass composition may be entered for the purpose of obtaining the desired physical properties while comparing such with the various component compounds. 
     A physical property (P) of glass, such as Young&#39;s modulus, can be expressed generally by the following formula: 
     
         P=ΣPiXi 
    
     where, 
     Pi: coefficient for the property of component compound i, 
     Xi: molar fraction for component compound i. 
     As Pi is an empirical value, the value of glass physical property (P) is of course an approximate value. 
     FIG. 6 depicts another embodiment of the computer-aided glass composition design apparatus of the present invention. 
     In this embodiment, as shown in FIG. 6, an appropriate composition is derived based on entered values of glass physical properties. More specifically, desired values of physical properties are entered using the display (5) as shown in FIG. 7. In this example, a Young&#39;s modulus&gt;1000, a density&lt;5, and a thermal expansion coefficient&lt;30 kare entered. 
     Compositions are determined by the calculating unit (4) which satisfy all the conditions of the entered physical property values or which satisfy only some of these conditions. For example, a composition comprising the following molar ratio values may be calculated and displayed as shown in FIG. 8: 
     
         ______________________________________                                    
        SiO.sub.2                                                         
              50.1                                                        
        Al.sub.2 O.sub.3                                                  
              39.9                                                        
        ZrO.sub.2                                                         
              10.0                                                        
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     Values of the other physical properties are then also displayed. 
     By comparing the composition and the values of the physical properties, the molar ratio of: 
     
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         SiO.sub.2                                                        
              60                                                          
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          may be entered again as a value similar to that displayed as
 above as shown in FIG. 9. As a result, a correspondence between the new
 composition and the physical properties is calculated and displayed as
 shown in FIG. 10.
 
    
     Of course, when calculation or comparison of a composition and physical property values is not possible in the case presented above, a display to that effect appears on the display unit (5) to urge re-entry. 
     To confirm a sufficient correlation between the calculated property values and actual property values, and to demonstrate the utility of the present invention, various tests were conducted which are described below as Example 1 and Example 2. 
     (1) Example 1 
     Comparisons were conducted between calculated Young&#39;s Modulus values and measured Young&#39;s Modulus values for the seven glass compositions Li 2  O-SiO 2 , Li 2  O-Al 2  O 3  -SiO 2 , MgO-CaO-Al 2  O 3  -SiO 2 , Na 2  O-TiO 2  -SiO 2 , PbO-SiO 2 , Na 2  O-K 2  O-PbO-Si 2  O, Na 2  O-K 2  O-PbO-ZnO-SiO 2 . FIG. 11 depicts the compared results. As is clear from FIG. 11, the calculated data correspond closely to actual measured data. 
     (2) Example 2 
     In yttria-aluminosilicate glass as a frame of Y 2  O 3  -Al 2  O 3  -SiO 2 , a new glass material having thermal expansion coefficient equal to about 100×10 -7  was designed. New compositions samples 1 and 2 were calculated. 
     
         ______________________________________                                    
       (sample 1)                                                         
       Na.sub.2 O                                                         
               15.0                                                       
       Al.sub.2 O.sub.3                                                   
               7.6                                                        
       Y.sub.2 O.sub.3                                                    
               5.4                                                        
       SiO.sub.2                                                          
               69.0                                                       
       ZrO.sub.2                                                          
               3.0                                                        
       (sample 2)                                                         
       Na.sub.2 O                                                         
               17.0                                                       
       Al.sub.2 O.sub.3                                                   
               7.6                                                        
       Y.sub.2 O.sub.3                                                    
               5.4                                                        
       SiO.sub.2                                                          
               70.0                                                       
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     Then, glass materials having compositions of samples 1 and 2 were actually synthesized in the following process. 
     Y 2  O 3 , Al 2  O 3 , Na 2  O, ZrO 2 , and acid-washed silica sand, or Y 2  O 3 , Al 2  O 3 , Na 2  O, and acid-washed silica sand were weighed and mixed. 50 g batches were melted in high-alumina crucibles for 3 h up to 1550° C. in an electric furnace with SiC heating elements. After 3 mm-diameter rods were drawn from the melt, the rods were annealed at about 30° C. above Tg (glass transition temperature) and cooled to room temperature. 
     The thermal expansion coefficient was measured for each manufactured glass and was compared with the calculated thermal expansion coefficient. FIG. 12 depicts the compared results. As is clear from FIG. 12, it is confirmed that the calculated thermal expansion coefficient corresponds closely to the actual measured thermal expansion coefficient. 
     Further, acid durability, alkaline durability, density, and microhardness of the manufactured glass materials having compositions of samples 1 and 2 were measured. For comparison purposes, properties of the commercial coating glass Li 2  O-Na 2  O-K 2  O-CaO-BaO-B 2  O 3  -ZrO 2  -SiO 2  were measured. Each test was performed as follows. 
     The glass rod samples were cut and their sharp edges were polished in order to avoid microcracking on the edges. After the dimensions of the rod were measured with a micrometer, the rod was washed three times with ethyl alcohol and then dried. These samples were weighed and then placed into a platinum-wire basket. 
     In the acid durability test, the basket and the rod samples were placed into an extractor. The glass rods were exposed alternately to the renewed vapor and liquid phase of 20 wt % HCl at 80±1° C. In the alkaline durability test, a plastic bottle in which the basket and the glass rods were soaked in 1N NaOH solution was settled in a silicone-oil bath at 80±1° C. In this test, the ratio of the NaOH solution volume to the sample surface area was kept constant at about 200 mL/cm 2  and the NaOH solution was renewed at 1-day intervals. The acid and alkaline durabilities were determined by observing the weight loss of the glass rod. 
     The density was measured using a powder of glass rod samples by the standard Archimedes method. The microhardness was measured with a Vickers hardness tester. In this case, a load of 50 g was applied for 15 s to the glass samples at room temperature and in the air. 
     In all tested properties, the new glass materials surpass the conventional commercial coating glass Li 2  O-Na 2  O-K 2  O-CaO-BaO-B 2  O 3  -ZrO 2  -SiO 2 . The new glass materials have higher chemical durability, for example, acid durability and alkaline durability, than that of the conventional glass. Microhardness and density of the new glass materials were also higher than those of the conventional glass. New glass materials for coating metal having excellent functions compared with the conventional commercial glass were found. 
     In the computer-aided glass design apparatus of the present invention, as described above, the composition of components composing glass and the physical properties thereof are simulated in an interactive manner to derive an optimum composition and physical properties of glass, thus permitting support of glass design for the achievement of a desired glass material. 
     The present invention thus allows considerable saving of time and labor which have largely been consumed in the conventional practices of designing of glass materials and permits calculation of values of physical properties on the basis of numerical information of glass raw materials, such as the atomic radius and dissociation energy, thus making it possible to easily accomplish at a very high efficiency design of a glass material of a desired composition and/or having desired physical properties through comparison of compositions and physical properties. 
     Furthermore, the present invention achieves the simulation of the design of glass materials which has not been previously realized.