Embodiment
Bulk conductive gloass provided by the invention, require it to have secondary electron emission characteristic, low volume specific resistance, to consider also that simultaneously glass is easy to found the use properties of moulding and glass (as easy processing, high strain-point), for this reason, the bulk conductive gloass of the present invention's design is the iron content silicate glass, and reasonable other oxide compounds of assembly, to reach effect of the presently claimed invention.
In the bulk conductive gloass of the present invention, include Na
2O, FeO, Fe
2O
3, SiO
2, MoO, Al
2O
3, TeO
2, and BaO.Wherein:
SiO
2Be the main component of glass, its content is the organizer of glass at 48-63%.
FeO, Fe
2O
3Lead composition for the main electricity in the glass of the present invention, the low volume specific resistance of glass mainly relies on Fe
2+/ Fe
3+The conduction chain realizes that its consumption of description of test of the present invention is also influential to the follow-up processing characteristics of stability, acid resistance and the glass of glass ware forming performance, glass volume specific resistance, glass;
Na
2O and Al
2O
3Be the ancillary component of glass of the present invention, they to the contribution of glass mainly founding aspect moulding and the follow-up processing characteristics, little to the volume specific resistance influence;
TeO
2Be the added ingredients in the glass of the present invention, can improve the devitrification resistance energy of glass, make the forming area of glass wideer;
BaO is another added ingredients in the glass of the present invention, adds the viscosity that can improve glass on a small quantity, increases the material of glass;
MoO is the another added ingredients in the glass of the present invention, adds moulding that helps glass on a small quantity and the volume specific resistance that reduces glass.
Above each composition is carried out reasonable assembly become the bulk conductive gloass of wanting required for the present invention.Composition and ratio that glass of the present invention can assembly have specifically been exemplified in the table 1.
Bulk conductive gloass of the present invention is according to design requirements, selects for use suitable raw material to form through high temperature melting by mole number.Raw material has Z 250, yellow soda ash, barium carbonate, molybdenum oxide etc., and wherein raw material is except that quartz sand adopts high-purity natural matter (80-120 order), and all the other all adopt analytically pure industrial chemicals.
Found process: each raw material that will calculate mixes, with ceramic crucible powder that (actual temp decide on material property) back adding prepares about stove internal heating to 1320 ℃, adopt reducing atmosphere to found, be incubated and be warmed up to about 1380 ℃ (actual temp is decided on material property) after 1 hour and be incubated 5 hours again, after glass clarifying is even, the uniform glass metal of fusion is poured on (temperature of mold heated is 480 ℃ of ANNEALING OF GLASS temperature) in the steel die that heats in advance, cast molding (sample in the present invention experiment be the long column shape of 65 * 12 * 12mm and the rectangle of 60 * 60 * 40mm), send in 480 ℃ the annealing furnace annealing then while hot after 2 hours, naturally cooling.
Performance test
The glass sample that obtains is carried out performance test respectively
1, secondary electron yield δ test
Material secondary electron emission coefficiency δ is defined as secondary electron stream I
sWith the ratio of primary electron stream Ip, promptly
δ=I
s/ Ip formula one
Testing method: adopt time of flight method to measure secondary electron yield δ method.
Test philosophy:
The ion beam current that accelerator produces enters predetermined beam corridor behind the magnet by analysis.First pair of deflector plate of line process 1kV (as shown in Figure 1) that adds high pressure, under effect of electric field, line downward bias is from the medullary ray of beam corridor.Line enters second pair of deflector plate then, and this deflector plate links to each other with the positive high voltage pulse that HTS produces, and the width of pulse and frequency are by the TTL signal control of millimicrosecond pulse generator, and the amplitude of high-voltage pulse can be regulated by high-voltage power supply, is generally the 5-10kV scope.Because second pair of deflector plate is opposite with the direction of an electric field of first pair of deflector plate, line then is reversed deflection.So only on second pair of deflector plate, reach certain voltage (V for example
0) time, the collimating aperture (3mm) that line just can pass on the medullary ray that is positioned at beam corridor is got on the sample, and the voltage on the second pair of deflector plate is higher or lower than V
0The time all do not have line to pass through collimating aperture, thereby realized the chopping of accelerator line.Below collimating aperture, there is one to have the rectangle Faraday cup that secondary electron is suppressed (lateral dimension of rim of a cup is 3mm, vertical dimension is 20mm) be used for measuring line, this structure can guarantee can not be subjected to the measurement of line the influence of beam configuration when experiment.The amplitude of experiment mesohigh pulse is far longer than the first pair of voltage on the deflector plate, and the width of high-voltage pulse generally is adjusted into 20 μ s, and the cycle is 20ms, so Faraday cup is accepted 99% line in the experiment.Because only (about 2ns) could allow line to pass through collimating aperture in the part-time of high-voltage pulse rising front.
The fast negative-going pulse in another road (be the ns magnitude fall time) synchronous with the TTL signal in the millimicrosecond pulse generator is imported into the fast timing discriminator, (be the ns magnitude fall time to the fast negative sense NIM signal of fast timing discriminator output, pulse height 0.7V) is input to the initiating terminal of multi channel scaling analyzer Turbo-MCS, the timing in road start time (pass).Specimen holder is made up of sample and aperture plate (transmitance is about 90%), the medullary ray of its normal direction and beam corridor angle at 45.Sample connects negative high voltage (10kV), and aperture plate is positioned at the preceding 8mm of sample, earthing potential.Pass aperture plate by the pulsed ionizing beam behind the collimating aperture and get on the sample, the secondary electron that produces from sample is quickened by the electric field between sample and the aperture plate, and the last energy that obtains of secondary electron is determined by the voltage between sample and the aperture plate.The secondary electron that obtains energy incides on microchannel plate (MCP) detector after passing the distance of aperture plate flight 40cm, the signal of MCP is input to another fast timing discriminator after the fast prime amplifier of VT120 amplifies, the fast negative sense NIM signal that the fast timing discriminator produces is input to the input terminus of multi channel scaling analyzer (Turbo-MCS), so just can measure the time of flight spectrum of secondary electron.Time of flight spectrum is by the integral charge numerical control system that sets on the Faraday cup.By analysis, can determine the secondary electron yield δ of sample to time of flight spectrum.
During experiment, the vacuum tightness in beam corridor and the target chamber is less than 10
-4Pa.
Specimen: will founding the glass preparation of the present invention that obtains, to become diameter be the circle of 25mm, and at the outside of glass circle plating Ni-Cr metallic membrane, glass circle mid-diameter is that 10mm partly exposes.
Experiment beam bombardment glass surface, the secondary electron yield δ of mensuration glass surface;
The present invention makes the secondary electron yield δ test data of glass and lists in table 1.Test result shows that the secondary electron yield δ of glass surface of the present invention has following feature:
1). secondary electron yield δ is with primary electron (Ip) ENERGY E p
0Do variation as shown in Figure 2, the primary electron ENERGY E
MaxWhen being about 380eV, δ reaches maximum value 2.6.
2). primary electron is from injecting δ with the direction of secondary emission surface inclination
MaxIncrease E
MaxAlso increase.
3). no matter primary electron from which direction direction is injected, and the secondary electron yield δ that sends with the secondary emission surface vertical direction is maximum.
4). secondary electron yield δ is basic and probe temperature is irrelevant.
5). the inner secondary electron number that produces of glass is along with the terminal point of primary electron stroke sharply increases, thereby along with E
0Increase, producing more secondary electron number near surface increases, δ increases; But E
0Increase too greatly, then most secondary electron number produces in the place darker from the surface, and the chance that reaches the surface reduces, and δ descends.
2, coefficient of expansion α
300Test
The specific elongation rate that object raises 1 ℃ the time is referred to as linear expansivity.
α=(L
t-L
0)/L
0(t-t
0) formula two
L
0---object is in temperature t
0The time length (m);
L
t---the length (m) when object is heated to temperature t.
α
300Just be meant from room temperature and be heated to average coefficient of linear expansion between 300 ℃.
Testing method: quartzy dilatometer method
Test philosophy: utilize thermal expansivity different of the glass sample place quartz glass tube and pure quartz glass, measure both specific elongations in heat-processed.
The glass bar of the long column shape of specimen: 65 * 12 * 12mm is cut into the 60mm height on cutting machine, and makes two faces parallel;
Testing tool: the QFB-T II coefficient of expansion determinator of physical and chemical measuring room of Beijing Glass Inst. development.
The present invention makes the coefficient of expansion α of glass
300Test data is listed in table 1.
3, direct current volume electricalresistivity
vTest
Get glass sample through the plate glass sheet that cuts, grinds, 40 * 40 * 30mm is made in polishing, utilize the volume specific resistance of galvanic current four circle electrode method (HZ-2513 megger) tested glass.
The volume specific resistance of system glass is with Fe
2O
3The molar content change curve referring to Fig. 3.As shown in Figure 3, under the constant situation of other conditions, work as Fe
2O
3Molar content when increasing, the volume specific resistance of glass reduces, and works as Fe
2O
3Molar content change at 14% o'clock from 8%, the volume specific resistance of glass is from 6.91 * 10
10Ω cm drops to 2.81 * 10
9Ω cm, an order of magnitude descends.
The volume specific resistance of system glass is with SiO
2The molar content change curve is referring to Fig. 4.As can be seen from Figure 4, work as SiO
2The resistivity that molar content increases glass increases, and this is because the SiO of system
2The structure of glass was fine and close more when molar content increased, Fe
2+/ Fe
3+The resistance of electronic migration is big more in the conduction chain, and the resistivity of glass increases.
The volume specific resistance ρ of embodiment of the invention glass
vTest data is enumerated table 1.
4, acid etching speed V test
Sample is respectively got about 5g, with electronic balance weighing record reading G
0Under the room temperature, HNO
3Concentration is 0.134mol/l, and soak time is 4hour, and it is dry that water is put into baking oven with sample wash after clean, and the cooling back is with electronic balance weighing record reading G
1Acid etching speed V according to formula 3 calculation samples.
Formula three
The acid etching speed V test data of embodiment of the invention glass is listed in table 1.
5, strain temperature Tg
Test philosophy: by the coefficient of expansion of test differing temps, make the coefficient of expansion-temperature curve, the coefficient of expansion-temperature slope intersection point is strain temperature point Tg.
The strain temperature Tg test data of embodiment of the invention glass is listed in table 1.
Table 1
| Embodiment 1 | Embodiment 2 | Embodiment 3 | Embodiment 4 | Embodiment 5 |
Composition | Ratio (mole %) |
SiO
2 |
56 |
55 |
55 |
54 |
48 |
Na
2O
|
23 |
23 |
22 |
22 |
23 |
Al
2O
3 |
9 |
9 |
9 |
9 |
9 |
Fe
2O
3 |
8 |
9 |
10 |
11 |
16 |
MoO |
2 |
2 |
2 |
2 |
2 |
TeO
2 |
1 |
1 |
1 |
1 |
1 |
BaO |
1 |
1 |
1 |
1 |
1 |
Test event |
Test result |
Tg(℃) |
498 |
487 |
485 |
478 |
452 |
α
300(×10
-7/℃)
|
99.6 |
100.8 |
101.3 |
104.6 |
115.8 |
ρ
v(×10
10Ωcm)
|
6.52 |
5.29 |
4.12 |
3.89 |
2.58 |
δ |
2.6 |
2.6 |
2.6 |
2.6 |
2.5 |
Acid etching speed V (%/h) |
0.0 |
0.0 |
0.0 |
0.0 |
0.5 |
Data show in the table, and all the secondary electron yield δ of embodiment all can reach more than 2.5 the volume specific resistance ρ of glass
vMinimumly drop to 2.58 * 10
10Ω cm, the glass that the embodiment of the invention is described can satisfy Aeronautics and Astronautics, electron trade has particular requirement to glass; Strain temperature Tg considerably beyond 260 ℃ of existing bulk conductive gloass, illustrates that the glass resistance toheat of the embodiment of the invention is good all above 450 ℃, can use in being no more than 450 ℃ environment; Acid etching speed V value is very little or be zero, illustrates that the conductive glass resistance to acid attack of the embodiment of the invention is functional; Coefficient of expansion α
300Be 104.6 * 10 to the maximum
-7/ ℃, illustrate that the hot workability of glass is good.
6, acid etching experiment back glass surface three-dimensional appearance
With the glass grinding of embodiment 3, the plate glass sheet that 10 * 10 * 1.0mm is made in polishing, this sheet glass is placed the HNO of 40 ℃ of following 0.134mol/l
3In, leave standstill and take out after stirring acid etching 60min.With atomic force microscope (Ouesant Instrument Co.Qscobe 250, AFM) its surface topography, roughness are analyzed, the variation of gained three-dimensional surface shape as shown in Figure 5, from the scanning of Fig. 5 row and column, find out, embodiment 3 glass surfaces do not have projection substantially, glass surface is smooth, and the acid resistance of glass is good.
The performance of different glass system relatively
Adopt same testing method, the present invention has compared the performance of different glass system.
1. Na
2O-V
2O
5-TeO
2System
Na
2O-V
2O
5-TeO
2The composition of system glass and transition point (T
g) see Table 2-1.In the table data as can be seen, though the volume specific resistance of this glass system is lower, glass ware forming difficulty, viscosity are also low, poor processability, in addition transition temperature point well below make, the requirement of processing.
Table 2-1 Na
2O-V
2O
5-TeO
2The composition of system and transition point
Numbering | Na
2O
| V
2O
5 | TeO
2 | T
g(℃)
| ρ
v(Ωcm)
|
HP11 | 4.0 | 27.33 | 68.67 | 247.5 | 7.94×10
7 |
HP12 | 5.48 | 24.04 | 70.48 | 245 | 2.51×10
8 |
HP13 | 8.67 | 16.92 | 74.4 | 238 | 6.30×10
9 |
2. Fe
3O
4-B
2O
3-SiO
2System
Table 2-2 is Fe
3O
4-B
2O
3-SiO
2A kind of typical glass formula of system and test result thereof.
Table 2-2 Fe
3O
4-B
2O
3-SiO
2System glass composition and performance
Numbering | Fe
3O
4 | B
2O
3 | SiO
2 | Other | Atmosphere | ρ(Ωcm) | Acid etching speed (%/h) | Tg(℃) | α
300(×10
-7/ ℃)
|
HP21 | 21 | 19.5 | 49 | 10.5 | Neutral | 4.6×10
11 | 15.6 | 556 | 65 |
HP22 | 21 | 19.5 | 49 | 10.5 | Reduction | 2×10
6 | 16.8 | 560 | 70 |
The characteristics of this system:
1. Fe
3O
4-B
2O
3-SiO
2It is very big that system is influenced by atmosphere, and the structure that can draw the glass that glass formula of the same race forms from the gap of the body resistivity of material under different atmospheric conditions is different.
The glass acid resistance that 2. can draw this prescription from the acid etching result is poor, and this mainly is owing to have B in the glass system
2O
3
3. the devitrification resistance of this glass can poor (referring to the SEM result of Fig. 6), can not bear repeatedly hot-work.
4. Fe in the process of founding
3O
4-B
2O
3-SiO
2It is narrow that system forms the zone, changes under the little situation at composition, and the phase-splitting of glass is serious, can not found out uniform frit side.
3. Na of the present invention
2O-Fe
2O
3-SiO
2System
Table 2-3 Na
2O-Fe
2O
3-SiO
2System performance
Na
2O
| Fe
2O
3 | SiO
2 | Other | Atmosphere | Tg(℃) | Tf(℃) | α
300(×10
-7/℃)
| ρ
v(× 10
10Ωcm)
|
20-25 | 8-16 | 48-63 | 9-14 | Reduction | 450-500 | 548-580 | 90-120 | 7.0-0.2 |
Na of the present invention
2O-Fe
2O
3-SiO
2System confirms that by the seebeck coefficient of tested glass glass is electronic conduction, and the mobility of normal temperature download stream and concentration are 0.99cm
2V
-1S
-1,-3.67 * 10
20Cm
-3Experiment shows Fe
2O
3Molar content was less than 12% o'clock, and the glass acid and alkali corrodes, and acid etching speed V is 0.Acid resistance can satisfy the requirement of cladding glass.The volume specific resistance of this system glass mainly is subjected to Fe
2O
3The influence of molar content.Under the constant situation of other conditions, work as Fe
2O
3Molar content change at 14% o'clock from 8%, the volume specific resistance of glass is from 1.09 * 10
11Ω cm drops to 6.73 * 10
9Ω cm.This system performance is founded atmosphere to be influenced, and changing atmosphere can be the volume specific resistance of glass from 6.73 * 10
9Ω cm drops to 2.81 * 10
9Ω cm, volume specific resistance can satisfy the requirement of making, processing.
On mechanism, the electrical conduction mechanism of iron content silicate glass of the present invention also can be explained with the SPH theory.The secondary emissionratio of iron content silicate glass provided by the invention possesses acid resistance more than 2, and strain point is all more than 500 ℃, has higher conductivity, good fusing and processing characteristics.